From the Society for Vascular Surgery
International experience with endovascular therapy of the ascending aorta with a dedicated endograft Nikolaos Tsilimparis, MD, PhD,a E. Sebastian Debus, MD, PhD,a Gustavo S. Oderich, MD,b Stephan Haulon, MD,c Kim Allan Terp, MD,d Blayne Roeder,e Christian Detter, MD, PhD,a and Tilo Kölbel, MD, PhD,a Hamburg Germany; Rochester, Minn; Lille, France; Aarhus, Denmark; and Bloomington, Ind Objective: The objective of this study was to evaluate the safety and feasibility of a novel stent graft specifically designed for treatment of the ascending aorta. Methods: This was a multicenter, retrospective analysis of all consecutive patients treated with the dedicated Zenith Ascend TAA Endovascular Graft (William Cook Europe, Bjaeverskov, Denmark) for pathologic processes requiring stent grafting of the ascending aorta. The graft is short (6.5 cm), with a delivery system designed for transfemoral placement in the ascending aorta. Results: In 10 patients (five men; age, 67 years; range, 26-90 years), the Zenith Ascend graft was implanted for the following indications: dissection (n [ 5) and aneurysm (n [ 4) of the ascending aorta and fixation of an intraprocedural dislocated aortic valve (n [ 1). All patients were judged to be at high risk for open surgery (nine patients were classified as American Society of Anesthesiologists class 3 or class 4). A transfemoral approach was selected in eight cases and a transapical approach in two. All endografts were successfully deployed without intraoperative adverse events at the targeted landing zone. Clinical success in coverage of the lesions was achieved in all cases with the exception of an attempted treatment of an intraprocedural aortic valve implantation dissection that resulted in early mortality. The 30-day survival was 90%. Early neurologic events included one patient with stroke and paraplegia and one patient with a transient ischemic attack. One patient underwent early evacuation of a hemopericardium. There were two late reinterventions for persisting endoleaks. At a mean follow-up of 10 months (range, 1-36 months), three late deaths occurred, with one treatment related, as a result of graft infection. Conclusions: Despite the fact that in this first published series the graft was frequently used as a “rescue tool” outside its intended indication, treatment with the Zenith Ascend graft in this early experience appears to be safe and feasible for repair of ascending aorta pathologic processes in high-risk patients unsuitable for open repair. (J Vasc Surg 2016;-:1-7.)
The ascending aorta has traditionally been the cradle of open cardiothoracic surgery. Whereas the outcomes of open repair are exceptional, with excellent durability in good-risk patients, open surgery is less favorable in highrisk groups with characteristics such as advanced age or prior cardiothoracic surgery, with a mortality of 13% to From the German Aortic Center, University Heart Center, Hamburga; the Department of Vascular and Endovascular Surgery, Mayo Clinic, Rochesterb; the Department of Vascular Surgery, Heart Center, University of Lille, Lillec; the Department of Cardiothoracic Surgery, University of Aarhus, Aarhusd; and the Cook Medical, Bloomington.e Author conflict of interest: G.S.O. receives consulting fees from Cook Medical. S.H. receives consulting fees from Cook Medical. B.R. is a Cook Medical salaried employee. T.K. has Cook Medical intellectual properties. Presented in the VI Vascular and Endovascular Surgery Society Paper Session 1 at the 2015 Vascular Annual Meeting of the Society for Vascular Surgery, Chicago, Ill, June 17-20, 2015. Correspondence: Nikolaos Tsilimparis, MD, PhD, Department of Vascular Medicine, University Heart Center, University Hospital HamburgEppendorf, Martinistr. 52, 20246 Hamburg, Germany (e-mail: [email protected]). The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a conflict of interest. 0741-5214 Copyright Ó 2016 by the Society for Vascular Surgery. Published by Elsevier Inc. http://dx.doi.org/10.1016/j.jvs.2015.12.027
38%.1-3 Furthermore, high-risk patients are frequently denied surgical therapy for life-threatening conditions, such as dissections or intramural hematomas of the ascending aorta, as the anticipated risks outweigh the expected benefit. During the past 10 years, a few cases of endovascular management of ascending aortic pathologic processes, most commonly type A aortic dissections (TAADs), have been published, confirming the feasibility of an endovascular approach to the ascending aorta.4-10 All patients described in these reports were treated with proximal extensions of thoracic endografts.11 The first successful management of an ascending aortic dissection with a dedicated ascending stent graft was reported in 2012 by Metcalfe et al.12 In this study, we report an international experience with implantation of the Zenith Ascend TAA Endovascular Graft (William Cook Europe, Bjaeverskov, Denmark), an endovascular graft that is designed specifically for pathologic processes requiring stent grafting of the ascending aorta. METHODS Study design. This was a multicenter, retrospective analysis of all consecutive patients treated with the dedicated Zenith Ascend TAA Endovascular Graft for pathologic processes requiring stent grafting of the ascending aorta. 1
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Fig 1. The Zenith Ascend TAA Endovascular Graft is constructed of woven polyester fabric sewn to self-expanding nitinol stents with braided polyester and monofilament polypropylene suture.
Primary end points of the study were procedural technical success and 30-day survival. Secondary end points included 30-day reintervention and any complications, long-term survival, stent-related outcomes including endoleaks, migration, and secondary interventions. Further collected items included patients’ demographic data and anatomic characteristics, procedural variables, and specific postoperative complications. Given the retrospective nature of the study and the lack of alternative treatment options for these patients, who were treated on an emergency basis or for palliation, no Institutional Review Board approval was required by the coordinating office for participation in the study. All subjects gave informed consent after thorough description of the investigational nature of the device and the alternative off-the-shelf options with other devices. Given the multicenter retrospective international nature of the study, each center independently proceeded with the Institutional Review Board process as required per institution. Device description. The Zenith Ascend TAA Endovascular Graft is a single-component tubular endograft. The stent graft is constructed of woven polyester fabric sewn to self-expanding nitinol stents with braided polyester and monofilament polypropylene suture (Fig 1). The graft design is based on the Zenith Alpha Thoracic graft (William Cook Europe) and incorporates uncovered stents on both the proximal and distal ends to facilitate accurate deployment, alignment, and apposition of the graft in the ascending aorta. Four radiopaque markers are positioned on each end of the stent graft in a circumferential orientation within 1 mm of the most proximal or distal aspect of the graft material to facilitate optimal visualization of the stent graft component. The device is currently produced with diameters of 28 to 46 mm and a covered length of 65 mm. Delivery system. The graft is preloaded on a 100-cm introduction system with a flexible, soft tip that has a sequential deployment method with features to provide continuous control of the endovascular graft throughout the deployment procedure. The endograft is deployed from a 16F, 18F, or 20F delivery system. To facilitate accurate deployment, the graft is
fixed to the delivery system in five locations along its length. The bare stents are fixated on both ends, and there are three circumferential sutures (Pro-Form Design, W. Cook Medical Europe, Bjaeverskov, Denmark) to constrain the covered portion of the device.13 In this way, minor repositioning is possible after retraction of the sheath, and the windsock effect is reduced during unsheathing as wall apposition of the endograft is not circumferential during the first deployment step. There is a single release mechanism to sequentially release the graft from the delivery system (Fig 2). The Zenith Ascend TAA Endovascular Graft requires an adequate proximal landing zone distal to any coronary orifice and a distal landing zone proximal to the innominate artery. The outer wall to outer wall diameter should not measure more than 40 mm or less than 24 mm. Technique. Typically, a transfemoral access is used, and an extrastiff wire is placed in the left ventricle across the aortic valve. Using vena cava occlusion technique, rapid pacing, or adenosine-induced cardiac arrest, left ventricular output is reduced, and the endograft is deployed under serial angiography at the intended landing zone. Transesophageal echocardiography was selectively used to facilitate accurate deployment. In the absence of sufficient transfemoral access, a transapical access can be used (Fig 3). Patient selection. Only selected patients were candidates for the Zenith Ascend TAA Endovascular Graft in the acute or elective setting. For patients in good general condition without significant comorbidities, open repair was the treatment of choice. High-risk patients with comorbidities prohibitive for open surgery were considered for endovascular repair. All patients were consented to the procedure, given the lack of a reasonable alternative treatment option. All elective cases were discussed in an interdisciplinary conference with cardiologists and cardiothoracic surgeons. Statistical analysis. Descriptive data analysis was performed using the SPSS Statistics version 21.0 (IBM Corp, Armonk, NY). RESULTS Between 2011 and 2014, a total of 10 patients were treated in four institutions with the dedicated Ascend graft for pathologic processes of the ascending aorta. The indications for treatment included dissection of the ascending aorta (n ¼ 5), aneurysm (n ¼ 4), and fixation of an intraprocedural dislocated aortic valve (n ¼ 1). Patient characteristics. The median age of the group (five men) was 70 years (range, 26-90 years). Four patients were classified as American Society of Anesthesiologists (ASA) risk class 3 and five patients as ASA class 4; only one patient was considered ASA class 2. The patients’ comorbidities are presented in Table I. Most patients (n ¼ 8; 80%) had prior cardiothoracic surgery, including two patients with prior heart transplantation and four patients with prior open ascending aorta repair for Stanford type A dissection. Three patients were
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Fig 2. In vitro deployment (a) of the Zenith Ascend TAA Endovascular Graft by pullback of the sheath. The graft is at this point still fixed proximally, distally, and with circumferential sutures (Pro-Form) in the covered portion to the delivery system (b), thus allowing flow through the graft and minor repositioning corrections.
Fig 3. Axial (a) and three-dimensional (b) computed tomography imaging of an aneurysm of the ascending aorta treated by transfemoral implantation of a Zenith Ascend graft. Angiography before (c) and after deployment (d) and the postoperative axial (e) and three-dimensional (f) computed tomography images confirm successful exclusion of the aneurysm.
treated in an acute setting (two type A dissections, one dislocated valve) and seven patients in an elective setting. Aneurysm and procedural characteristics. The median maximal diameter of the ascending aorta was
54 mm (range, 30-80 mm) (Table II). Four patients (40%) underwent preoperative cervical debranching. Three of these debranching procedures were performed to facilitate endovascular procedures other than the ascending
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Table I. Comorbidities of the patient cohort
Hypertension Hyperlipidemia Smoking history COPD Home oxygen Diabetes mellitus Peripheral arterial disease Renal insufficiency Connective tissue disorders Coronary artery disease Atrial fibrillation History of myocardial infarction Congestive heart failure Prior CABG Previous cardiothoracic surgery
No.
%
8 6 6 4 2 0 3 0 0 8 6 5 6 3 8
80 60 60 40 20 d 30 d d 80 60 50 60 30 80
CABG, Coronary artery bypass grafting; COPD, chronic obstructive pulmonary disease.
stent graft, including two left carotid-subclavian bypasses and one left subclavian artery transposition. A carotidcarotid bypass with reimplantation of the left common carotid in the left subclavian artery was performed to achieve distal landing zone for the Ascend stent graft in one patient. A transfemoral approach was selected in eight cases and a transapical approach in two cases because of poor transfemoral access. One patient with mechanical aortic valve required additional ascending aortic access over median sternotomy, and a conduit graft was sewn on his ascending aorta to facilitate a through-and-through wire and externalization of the tip of the graft. Besides cervical debranching, other simultaneous procedures included implantation of one fenestrated and one branched arch endograft (n ¼ 2) in patients with concomitant arch disease. As suggested in the indications, another two patients underwent minimally invasive implantation of an aortic valve, resulting in the need for implantation of the Ascend endograft. The operating time ranged from 54 to 360 minutes. Because of concurrent surgical procedures, such as cervical debranching, it was difficult to retrospectively report the exact time related to implantation of the Ascend graft. Early outcomes. All endografts were successfully deployed without intraoperative adverse events at the targeted landing zone. Clinical success in coverage of the lesions was achieved in all cases with the exception of an attempted treatment of an intraprocedural aortic valve implantation dissection. The specific patient had a persistent type Ia endoleak, which resulted in early death a few hours after the procedure. This was also the single 30-day or in-hospital death, resulting in a cumulative early survival of 90%. Retrospective analysis of the patient’s computed tomography scan revealed a diameter of 48 mm at the landing zone, prohibiting sealing of the stent graft. The patient treated with additional primary sternotomy suffered multiple postoperative complications, including
bleeding, stroke, pneumonia, and hemopericardium requiring surgical evacuation. That specific patient also developed transient spinal cord ischemia that completely recovered and acute renal failure; he had a prolonged 22-day stay in the intensive care unit and was discharged to a rehabilitation center on postoperative day 36. All remaining patients had no major postoperative complications. Minor postoperative events included transient worsening of renal function that returned to baseline and a minor femoral wound dehiscence that was treated successfully. The median length of intensive care unit stay was 1 day (range, 1-22 days), and the median in-hospital stay was 10 days (range, 2-36 days). Of the nine survivors, seven were discharged to home and two were discharged to rehabilitation institutions in good functional status. All patients received a postoperative computed tomography scan before discharge. There was one persistent perfusion of the dissection distal to the endograft that was initially treated conservatively. All other grafts (n ¼ 8) were without any signs of false lumen perfusion or endoleak. Late outcomes. The mean follow-up was 12 months (range, 0-36 months). During this time, there were two Ascend graft-related reinterventions and three late deaths occurred, of which one was repair/aneurysm related. Both reinterventions were performed for endoleaks (one primary and one secondary endoleak), and both included implantation of another stent graft. One patient with a complicated postoperative course, who had been discharged to rehabilitation, eventually died of sepsis after prostatitis unrelated to the stent graft repair 3 months after the initial operation. The patient with a type I endoleak had an increase in aneurysm size, resulting in bleeding and cutaneous fistulization that was treated with another standard thoracic endograft. This patient eventually developed stent graft infection and died 3 months postoperatively after chronic graft infection, sepsis, and chronic pericardial effusion. The third patient died 12 months after the index procedure as a result of rapid progression of a bronchial carcinoma that was diagnosed on follow-up. DISCUSSION Open surgical repair of the ascending aorta, with or without replacement of the aortic valve, is typically performed for acute type A dissections requiring emergent surgical repair. Patients with aneurysmal disease of the ascending aorta will most commonly require partial arch replacement or frozen elephant trunk procedures. Whereas open surgery has excellent results in good-risk patients, especially when the repair is restricted to an ascending conduit,14,15 a significant portion of patients are denied operative treatment because of the poor estimated surgical outcome. Mehta et al showed that patients >70 years treated for TAAD had a 1.7-fold higher risk for early mortality compared with patients 48 hours after the index symptoms.19 Anatomic limitations make a complete endovascular repair of the ascending aorta with the currently available endografts often impossible. Jaussaud et al20 identified the location of intimal tear, aortic valve insufficiency, and aortic
diameter >38 mm as the major factors limiting the use of standard thoracic stent grafts for TAAD. Sobocinski et al,21 on the other hand, reviewed a series of 102 patients to conclude that approximately half of the patients undergoing an open repair for TAAD could potentially benefit from an endovascular repair if appropriate stent grafts were used. In the study of Moon et al,22 only 32% of the cases examined appeared to be anatomically amenable to endovascular repair of the ascending aorta, with the most common exclusion finding being the absence of a proximal landing zone in 36% of the rejected cases. Similarly, Huang et al concluded in their study in an Asian population that 38% of their patients with TAAD could potentially be treated by stent grafting.23 The introduction of endovascular techniques in the aortic arch and ascending aorta has significantly expanded the therapeutic spectrum, and several reports have indicated the feasibility of stent grafting in the ascending
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aorta.4-7,10,24 In all these reports, however, standard thoracic devices have been used, whereas Ronchey et al reported the treatment of two patients with a stent graft with shorter tip to better accommodate the ascending aorta. The need for a device design specifically designed to cope with the challenges of implanting a stent graft very close to the coronary vessels, after accommodating severe angulations of the arch and extreme hemodynamic forces, is obvious. The configuration of standard thoracic endografts may cause disastrous complications, such as injury of the aortic valve or the left ventricle, by the long and inflexible introducer tips of standard endografts. The Zenith Ascend TAA Endovascular Graft with its soft, flexible tip and its controlled staged deployment has met many of these urgently needed modifications to serve the needs of the ascending aorta. In this series, we report a multicenter experience with the Ascend graft for a variety of indications. Given that open repair remains the standard of care for the ascending aorta in all participating institutions, the cases represent a negative selection with high technical difficulty and comorbid status that would alternatively be treated conservatively. The early results are promising, with a 30-day mortality of 10%; the single early death occurred in a patient who emergently received an Ascend aortic graft as a bailout procedure after intraoperative TAAD during complex transfemoral aortic valve repair. In that particular case, the graft was also undersized in comparison to the native aorta, thus not achieving proximal seal and resulting in clinical failure to exclude the dissection. The 10 patients studied in this paper were treated for a variety of indications and even included unusual indications, such as fixation of an aortic valve at the wall of the ascending aorta. The unusual and challenging indications could explain the early mortality and the need for reintervention as well as the graft infection in the cohort. Reinterventions in such a cohort of patients do not represent a treatment failure but rather the completion of the repair of a complex disease, which even when treated by open surgery would require additional management. Another key point that can be extrapolated by the present series is that in the absence of an adequate transfemoral approach, the transapical approach is a feasible alternative in these patients. It worked sufficiently with accurate graft deployment in two cases. Although an infrarenal or iliac conduit is also a good option in these patients, we would choose to avoid such an access in patients with residual dissection of the thoracoabdominal aorta. The transapical approach also allows more accurate stent graft positioning. The decision as to whether the access should be transfemoral, over iliac conduit, or transapical should be individualized after consideration of anticipated difficulties in the target zone and in the access region. In contrast to previous reports regarding endovascular repair of the ascending aorta, we have not found an oversizing of 20% or more to promote aortic valve
insufficiency.5 In contrast, we would strongly recommend at least 20% oversizing in native ascending aorta to avoid possible undersizing, especially in consideration of the variation of 15% in diameter observed in the native ascending aorta and arch during the cardiac cycle.25 Although traditionally a seal zone of at least 20 mm is required for aneurysms and dissections in the descending aorta, the use of the Ascend endovascular graft with its accurate, staged deployment mechanism could possibly enable successful treatment of pathologic processes even with a landing zone of 10 mm distal to the coronary orifices and a distal landing zone of at least 10 mm proximal to the innominate artery. The role of the Ascend graft in type A dissections still needs to be defined in larger series. Next to the proximal and distal landing zone, the diameter of the proximal landing zone should not exceed 38 mm or be below 24 mm. The length of the ascending aorta in the outer curvature should be at least 65 mm to accommodate the graft. In the case of an inadequate distal landing zone or a short length of the ascending aorta, it is possible to improve the distal landing zone by performing cervical debranching or extending the endovascular repair with fenestrated or branched arch endograft. Limitations. Major limitations of the study include the restricted sample size with 10 patients treated during a 4-year period and a restricted median follow-up of 10 months. Another major limitation is the variability of indications for treatment with the specific endograft and its compassionate use only, thus possibly not doing justice to the endograft’s performance. CONCLUSIONS Open repair of ascending aortic pathologic processes remains the “gold standard,” but its effectiveness is limited in high-risk patients, such as patients with prior cardiothoracic surgery or advanced age, because of the relevant perioperative morbidity and mortality. The present series provides encouraging evidence for the safety and feasibility of a device specific for treatment of ascending aortic diseases, although larger studies are required to confirm safety and to prove effectiveness of the stent graft. AUTHOR CONTRIBUTIONS Conception and design: NT, TK Analysis and interpretation: NT, ED, GO, SH, KT, BR, CD, TK Data collection: NT, GO, SH, KT, BR, CD, TK Writing the article: NT, TK Critical revision of the article: NT, ED, GO, SH, KT, BR, CD, TK Final approval of the article: NT, ED, GO, SH, KT, BR, CD, TK Statistical analysis: NT Obtained funding: Not applicable Overall responsibility: NT
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REFERENCES 1. Kilic A, Tang R, Whitson BA, Sirak JH, Sai-Sudhakar CB, Crestanello J, et al. Outcomes in the current surgical era following operative repair of acute type A aortic dissection in the elderly: a singleinstitutional experience. Interact Cardiovasc Thorac Surg 2013;17: 104-9. 2. Yeh YH, Su YJ, Liu CH. Acute aortic dissection (AAD) in the elderly. Arch Gerontol Geriatr 2013;57:78-80. 3. Shiono M, Hata M, Sezai A, Iida M, Yagi S, Negishi N. Emergency surgery for acute type A aortic dissection in octogenarians. Ann Thorac Surg 2006;82:554-9. 4. Idrees J, Arafat A, Johnston DR, Svensson LG, Roselli EE. Repair of retrograde ascending dissection after descending stent grafting. J Thorac Cardiovasc Surg 2014;147:151-4. 5. Ronchey S, Serrao E, Alberti V, Fazzini S, Trimarchi S, Tolenaar JL, et al. Endovascular stenting of the ascending aorta for type A aortic dissections in patients at high risk for open surgery. Eur J Vasc Endovasc Surg 2013;45:475-80. 6. Zhang H, Li M, Jin W, Wang Z. Endoluminal and surgical treatment for the management of Stanford type A aortic dissection. Eur J Cardiothorac Surg 2004;26:857-9. 7. Ihnken K, Sze D, Dake MD, Fleischmann D, Van der Starre P, Robbins R. Successful treatment of a Stanford type A dissection by percutaneous placement of a covered stent graft in the ascending aorta. J Thorac Cardiovasc Surg 2004;127:1808-10. 8. Zimpfer D, Czerny M, Kettenbach J, Schoder M, Wolner E, Lammer J, et al. Treatment of an acute type B dissection with an intramural haematoma in the ascending aorta by percutaneous endovascular stentgraft placement. Thorac Cardiovasc Surg 2006;54:500-1. 9. Roselli EE, Idrees J, Greenberg RK, Johnston DR, Lytle BW. Endovascular stent grafting for ascending aorta repair in high-risk patients. J Thorac Cardiovasc Surg 2015;149:144-51. 10. Ye C, Chang G, Li S, Hu Z, Yao C, Chen W, et al. Endovascular stentgraft treatment for Stanford type A aortic dissection. Eur J Vasc Endovasc Surg 2011;42:787-94. 11. Nordon IM, Hinchliffe RJ, Morgan R, Loftus IM, Jahangiri M, Thompson MM. Progress in endovascular management of type A dissection. Eur J Vasc Endovasc Surg 2012;44:406-10. 12. Metcalfe MJ, Karthikesalingam A, Black SA, Loftus IM, Morgan R, Thompson MM. The first endovascular repair of an acute type A dissection using an endograft designed for the ascending aorta. J Vasc Surg 2012;55:220-2. 13. Kolbel T, Resch TA, Dias N, Bjorses K, Sonesson B, Malina M. Staged proximal deployment of the Zenith TX2 thoracic stent-graft: a novel
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technique to improve conformance to the aortic arch. J Endovasc Ther 2009;16:598-602. Galloway AC, Colvin SB, LaMendola CL, Hurwitz JB, Baumann FG, Harris LJ, et al. Ten-year operative experience with 165 aneurysms of the ascending aorta and aortic arch. Circulation 1989;80(Pt 1):I249-56. Rylski B, Hoffmann I, Beyersdorf F, Suedkamp M, Siepe M, Nitsch B, et al. Acute aortic dissection type A: age-related management and outcomes reported in the German Registry for Acute Aortic Dissection Type A (GERAADA) of over 2000 patients. Ann Surg 2014;259:598-604. Mehta RH, O’Gara PT, Bossone E, Nienaber CA, Myrmel T, Cooper JV, et al. Acute type A aortic dissection in the elderly: clinical characteristics, management, and outcomes in the current era. J Am Coll Cardiol 2002;40:685-92. Meszaros I, Morocz J, Szlavi J, Schmidt J, Tornoci L, Nagy L, et al. Epidemiology and clinicopathology of aortic dissection. Chest 2000;117:1271-8. Hagan PG, Nienaber C, Isselbacher EM, Bruckman D, Karavite DJ, Russman PL, et al. The International Registry of Acute Aortic Dissection (IRAD): new insights into an old disease. JAMA 2000;283:897-903. Feldman M, Shah M, Elefteriades JA. Medical management of acute type A aortic dissection. Ann Thorac Cardiovasc Surg 2009;15:286-93. Jaussaud N, Chitsaz S, Meadows A, Wintermark M, Cambronero N, Azadani AN, et al. Acute type A aortic dissection intimal tears by 64slice computed tomography: a role for endovascular stent-grafting? J Cardiovasc Surg 2013;54:373-81. Sobocinski J, O’Brien N, Maurel B, Bartoli M, Goueffic Y, Sassard T, et al. Endovascular approaches to acute aortic type A dissection: a CTbased feasibility study. Eur J Vasc Endovasc Surg 2011;42:442-7. Moon MC, Greenberg RK, Morales JP, Martin Z, Lu Q, Dowdall JF, et al. Computed tomography-based anatomic characterization of proximal aortic dissection with consideration for endovascular candidacy. J Vasc Surg 2011;53:942-9. Huang DP, Ye XH, Xiang YQ, Zhang XH. Thymectomy in central lymph node dissection for papillary thyroid cancer. Int J Clin Exp Med 2014;7:1135-9. Zimpfer D, Czerny M, Kettenbach J, Schoder M, Wolner E, Lammer J, et al. Treatment of acute type A dissection by percutaneous endovascular stent-graft placement. Ann Thorac Surg 2006;82:747-9. van Prehn J, Vincken KL, Muhs BE, Barwegen GK, Bartels LW, Prokop M, et al. Toward endografting of the ascending aorta: insight into dynamics using dynamic cine-CTA. J Endovasc Ther 2007;14: 551-60.
Submitted Sep 11, 2015; accepted Dec 15, 2015.
International experience with endovascular therapy of the ascending aorta with a dedicated endograft Nikolaos Tsilimparis, MD, PhD,a E. Sebastian Debus, MD, PhD,a Gustavo S. Oderich, MD,b Stephan Haulon, MD,c Kim Allan Terp, MD,d Blayne Roeder,e Christian Detter, MD, PhD,a and Tilo Kölbel, MD, PhD,a Hamburg Germany; Rochester, Minn; Lille, France; Aarhus, Denmark; and Bloomington, Ind Objective: The objective of this study was to evaluate the safety and feasibility of a novel stent graft specifically designed for treatment of the ascending aorta. Methods: This was a multicenter, retrospective analysis of all consecutive patients treated with the dedicated Zenith Ascend TAA Endovascular Graft (William Cook Europe, Bjaeverskov, Denmark) for pathologic processes requiring stent grafting of the ascending aorta. The graft is short (6.5 cm), with a delivery system designed for transfemoral placement in the ascending aorta. Results: In 10 patients (five men; age, 67 years; range, 26-90 years), the Zenith Ascend graft was implanted for the following indications: dissection (n [ 5) and aneurysm (n [ 4) of the ascending aorta and fixation of an intraprocedural dislocated aortic valve (n [ 1). All patients were judged to be at high risk for open surgery (nine patients were classified as American Society of Anesthesiologists class 3 or class 4). A transfemoral approach was selected in eight cases and a transapical approach in two. All endografts were successfully deployed without intraoperative adverse events at the targeted landing zone. Clinical success in coverage of the lesions was achieved in all cases with the exception of an attempted treatment of an intraprocedural aortic valve implantation dissection that resulted in early mortality. The 30-day survival was 90%. Early neurologic events included one patient with stroke and paraplegia and one patient with a transient ischemic attack. One patient underwent early evacuation of a hemopericardium. There were two late reinterventions for persisting endoleaks. At a mean follow-up of 10 months (range, 1-36 months), three late deaths occurred, with one treatment related, as a result of graft infection. Conclusions: Despite the fact that in this first published series the graft was frequently used as a “rescue tool” outside its intended indication, treatment with the Zenith Ascend graft in this early experience appears to be safe and feasible for repair of ascending aorta pathologic processes in high-risk patients unsuitable for open repair. (J Vasc Surg 2016;-:1-7.)
The ascending aorta has traditionally been the cradle of open cardiothoracic surgery. Whereas the outcomes of open repair are exceptional, with excellent durability in good-risk patients, open surgery is less favorable in highrisk groups with characteristics such as advanced age or prior cardiothoracic surgery, with a mortality of 13% to From the German Aortic Center, University Heart Center, Hamburga; the Department of Vascular and Endovascular Surgery, Mayo Clinic, Rochesterb; the Department of Vascular Surgery, Heart Center, University of Lille, Lillec; the Department of Cardiothoracic Surgery, University of Aarhus, Aarhusd; and the Cook Medical, Bloomington.e Author conflict of interest: G.S.O. receives consulting fees from Cook Medical. S.H. receives consulting fees from Cook Medical. B.R. is a Cook Medical salaried employee. T.K. has Cook Medical intellectual properties. Presented in the VI Vascular and Endovascular Surgery Society Paper Session 1 at the 2015 Vascular Annual Meeting of the Society for Vascular Surgery, Chicago, Ill, June 17-20, 2015. Correspondence: Nikolaos Tsilimparis, MD, PhD, Department of Vascular Medicine, University Heart Center, University Hospital HamburgEppendorf, Martinistr. 52, 20246 Hamburg, Germany (e-mail: [email protected]). The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a conflict of interest. 0741-5214 Copyright Ó 2016 by the Society for Vascular Surgery. Published by Elsevier Inc. http://dx.doi.org/10.1016/j.jvs.2015.12.027
38%.1-3 Furthermore, high-risk patients are frequently denied surgical therapy for life-threatening conditions, such as dissections or intramural hematomas of the ascending aorta, as the anticipated risks outweigh the expected benefit. During the past 10 years, a few cases of endovascular management of ascending aortic pathologic processes, most commonly type A aortic dissections (TAADs), have been published, confirming the feasibility of an endovascular approach to the ascending aorta.4-10 All patients described in these reports were treated with proximal extensions of thoracic endografts.11 The first successful management of an ascending aortic dissection with a dedicated ascending stent graft was reported in 2012 by Metcalfe et al.12 In this study, we report an international experience with implantation of the Zenith Ascend TAA Endovascular Graft (William Cook Europe, Bjaeverskov, Denmark), an endovascular graft that is designed specifically for pathologic processes requiring stent grafting of the ascending aorta. METHODS Study design. This was a multicenter, retrospective analysis of all consecutive patients treated with the dedicated Zenith Ascend TAA Endovascular Graft for pathologic processes requiring stent grafting of the ascending aorta. 1
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Fig 1. The Zenith Ascend TAA Endovascular Graft is constructed of woven polyester fabric sewn to self-expanding nitinol stents with braided polyester and monofilament polypropylene suture.
Primary end points of the study were procedural technical success and 30-day survival. Secondary end points included 30-day reintervention and any complications, long-term survival, stent-related outcomes including endoleaks, migration, and secondary interventions. Further collected items included patients’ demographic data and anatomic characteristics, procedural variables, and specific postoperative complications. Given the retrospective nature of the study and the lack of alternative treatment options for these patients, who were treated on an emergency basis or for palliation, no Institutional Review Board approval was required by the coordinating office for participation in the study. All subjects gave informed consent after thorough description of the investigational nature of the device and the alternative off-the-shelf options with other devices. Given the multicenter retrospective international nature of the study, each center independently proceeded with the Institutional Review Board process as required per institution. Device description. The Zenith Ascend TAA Endovascular Graft is a single-component tubular endograft. The stent graft is constructed of woven polyester fabric sewn to self-expanding nitinol stents with braided polyester and monofilament polypropylene suture (Fig 1). The graft design is based on the Zenith Alpha Thoracic graft (William Cook Europe) and incorporates uncovered stents on both the proximal and distal ends to facilitate accurate deployment, alignment, and apposition of the graft in the ascending aorta. Four radiopaque markers are positioned on each end of the stent graft in a circumferential orientation within 1 mm of the most proximal or distal aspect of the graft material to facilitate optimal visualization of the stent graft component. The device is currently produced with diameters of 28 to 46 mm and a covered length of 65 mm. Delivery system. The graft is preloaded on a 100-cm introduction system with a flexible, soft tip that has a sequential deployment method with features to provide continuous control of the endovascular graft throughout the deployment procedure. The endograft is deployed from a 16F, 18F, or 20F delivery system. To facilitate accurate deployment, the graft is
fixed to the delivery system in five locations along its length. The bare stents are fixated on both ends, and there are three circumferential sutures (Pro-Form Design, W. Cook Medical Europe, Bjaeverskov, Denmark) to constrain the covered portion of the device.13 In this way, minor repositioning is possible after retraction of the sheath, and the windsock effect is reduced during unsheathing as wall apposition of the endograft is not circumferential during the first deployment step. There is a single release mechanism to sequentially release the graft from the delivery system (Fig 2). The Zenith Ascend TAA Endovascular Graft requires an adequate proximal landing zone distal to any coronary orifice and a distal landing zone proximal to the innominate artery. The outer wall to outer wall diameter should not measure more than 40 mm or less than 24 mm. Technique. Typically, a transfemoral access is used, and an extrastiff wire is placed in the left ventricle across the aortic valve. Using vena cava occlusion technique, rapid pacing, or adenosine-induced cardiac arrest, left ventricular output is reduced, and the endograft is deployed under serial angiography at the intended landing zone. Transesophageal echocardiography was selectively used to facilitate accurate deployment. In the absence of sufficient transfemoral access, a transapical access can be used (Fig 3). Patient selection. Only selected patients were candidates for the Zenith Ascend TAA Endovascular Graft in the acute or elective setting. For patients in good general condition without significant comorbidities, open repair was the treatment of choice. High-risk patients with comorbidities prohibitive for open surgery were considered for endovascular repair. All patients were consented to the procedure, given the lack of a reasonable alternative treatment option. All elective cases were discussed in an interdisciplinary conference with cardiologists and cardiothoracic surgeons. Statistical analysis. Descriptive data analysis was performed using the SPSS Statistics version 21.0 (IBM Corp, Armonk, NY). RESULTS Between 2011 and 2014, a total of 10 patients were treated in four institutions with the dedicated Ascend graft for pathologic processes of the ascending aorta. The indications for treatment included dissection of the ascending aorta (n ¼ 5), aneurysm (n ¼ 4), and fixation of an intraprocedural dislocated aortic valve (n ¼ 1). Patient characteristics. The median age of the group (five men) was 70 years (range, 26-90 years). Four patients were classified as American Society of Anesthesiologists (ASA) risk class 3 and five patients as ASA class 4; only one patient was considered ASA class 2. The patients’ comorbidities are presented in Table I. Most patients (n ¼ 8; 80%) had prior cardiothoracic surgery, including two patients with prior heart transplantation and four patients with prior open ascending aorta repair for Stanford type A dissection. Three patients were
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Fig 2. In vitro deployment (a) of the Zenith Ascend TAA Endovascular Graft by pullback of the sheath. The graft is at this point still fixed proximally, distally, and with circumferential sutures (Pro-Form) in the covered portion to the delivery system (b), thus allowing flow through the graft and minor repositioning corrections.
Fig 3. Axial (a) and three-dimensional (b) computed tomography imaging of an aneurysm of the ascending aorta treated by transfemoral implantation of a Zenith Ascend graft. Angiography before (c) and after deployment (d) and the postoperative axial (e) and three-dimensional (f) computed tomography images confirm successful exclusion of the aneurysm.
treated in an acute setting (two type A dissections, one dislocated valve) and seven patients in an elective setting. Aneurysm and procedural characteristics. The median maximal diameter of the ascending aorta was
54 mm (range, 30-80 mm) (Table II). Four patients (40%) underwent preoperative cervical debranching. Three of these debranching procedures were performed to facilitate endovascular procedures other than the ascending
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Table I. Comorbidities of the patient cohort
Hypertension Hyperlipidemia Smoking history COPD Home oxygen Diabetes mellitus Peripheral arterial disease Renal insufficiency Connective tissue disorders Coronary artery disease Atrial fibrillation History of myocardial infarction Congestive heart failure Prior CABG Previous cardiothoracic surgery
No.
%
8 6 6 4 2 0 3 0 0 8 6 5 6 3 8
80 60 60 40 20 d 30 d d 80 60 50 60 30 80
CABG, Coronary artery bypass grafting; COPD, chronic obstructive pulmonary disease.
stent graft, including two left carotid-subclavian bypasses and one left subclavian artery transposition. A carotidcarotid bypass with reimplantation of the left common carotid in the left subclavian artery was performed to achieve distal landing zone for the Ascend stent graft in one patient. A transfemoral approach was selected in eight cases and a transapical approach in two cases because of poor transfemoral access. One patient with mechanical aortic valve required additional ascending aortic access over median sternotomy, and a conduit graft was sewn on his ascending aorta to facilitate a through-and-through wire and externalization of the tip of the graft. Besides cervical debranching, other simultaneous procedures included implantation of one fenestrated and one branched arch endograft (n ¼ 2) in patients with concomitant arch disease. As suggested in the indications, another two patients underwent minimally invasive implantation of an aortic valve, resulting in the need for implantation of the Ascend endograft. The operating time ranged from 54 to 360 minutes. Because of concurrent surgical procedures, such as cervical debranching, it was difficult to retrospectively report the exact time related to implantation of the Ascend graft. Early outcomes. All endografts were successfully deployed without intraoperative adverse events at the targeted landing zone. Clinical success in coverage of the lesions was achieved in all cases with the exception of an attempted treatment of an intraprocedural aortic valve implantation dissection. The specific patient had a persistent type Ia endoleak, which resulted in early death a few hours after the procedure. This was also the single 30-day or in-hospital death, resulting in a cumulative early survival of 90%. Retrospective analysis of the patient’s computed tomography scan revealed a diameter of 48 mm at the landing zone, prohibiting sealing of the stent graft. The patient treated with additional primary sternotomy suffered multiple postoperative complications, including
bleeding, stroke, pneumonia, and hemopericardium requiring surgical evacuation. That specific patient also developed transient spinal cord ischemia that completely recovered and acute renal failure; he had a prolonged 22-day stay in the intensive care unit and was discharged to a rehabilitation center on postoperative day 36. All remaining patients had no major postoperative complications. Minor postoperative events included transient worsening of renal function that returned to baseline and a minor femoral wound dehiscence that was treated successfully. The median length of intensive care unit stay was 1 day (range, 1-22 days), and the median in-hospital stay was 10 days (range, 2-36 days). Of the nine survivors, seven were discharged to home and two were discharged to rehabilitation institutions in good functional status. All patients received a postoperative computed tomography scan before discharge. There was one persistent perfusion of the dissection distal to the endograft that was initially treated conservatively. All other grafts (n ¼ 8) were without any signs of false lumen perfusion or endoleak. Late outcomes. The mean follow-up was 12 months (range, 0-36 months). During this time, there were two Ascend graft-related reinterventions and three late deaths occurred, of which one was repair/aneurysm related. Both reinterventions were performed for endoleaks (one primary and one secondary endoleak), and both included implantation of another stent graft. One patient with a complicated postoperative course, who had been discharged to rehabilitation, eventually died of sepsis after prostatitis unrelated to the stent graft repair 3 months after the initial operation. The patient with a type I endoleak had an increase in aneurysm size, resulting in bleeding and cutaneous fistulization that was treated with another standard thoracic endograft. This patient eventually developed stent graft infection and died 3 months postoperatively after chronic graft infection, sepsis, and chronic pericardial effusion. The third patient died 12 months after the index procedure as a result of rapid progression of a bronchial carcinoma that was diagnosed on follow-up. DISCUSSION Open surgical repair of the ascending aorta, with or without replacement of the aortic valve, is typically performed for acute type A dissections requiring emergent surgical repair. Patients with aneurysmal disease of the ascending aorta will most commonly require partial arch replacement or frozen elephant trunk procedures. Whereas open surgery has excellent results in good-risk patients, especially when the repair is restricted to an ascending conduit,14,15 a significant portion of patients are denied operative treatment because of the poor estimated surgical outcome. Mehta et al showed that patients >70 years treated for TAAD had a 1.7-fold higher risk for early mortality compared with patients 48 hours after the index symptoms.19 Anatomic limitations make a complete endovascular repair of the ascending aorta with the currently available endografts often impossible. Jaussaud et al20 identified the location of intimal tear, aortic valve insufficiency, and aortic
diameter >38 mm as the major factors limiting the use of standard thoracic stent grafts for TAAD. Sobocinski et al,21 on the other hand, reviewed a series of 102 patients to conclude that approximately half of the patients undergoing an open repair for TAAD could potentially benefit from an endovascular repair if appropriate stent grafts were used. In the study of Moon et al,22 only 32% of the cases examined appeared to be anatomically amenable to endovascular repair of the ascending aorta, with the most common exclusion finding being the absence of a proximal landing zone in 36% of the rejected cases. Similarly, Huang et al concluded in their study in an Asian population that 38% of their patients with TAAD could potentially be treated by stent grafting.23 The introduction of endovascular techniques in the aortic arch and ascending aorta has significantly expanded the therapeutic spectrum, and several reports have indicated the feasibility of stent grafting in the ascending
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aorta.4-7,10,24 In all these reports, however, standard thoracic devices have been used, whereas Ronchey et al reported the treatment of two patients with a stent graft with shorter tip to better accommodate the ascending aorta. The need for a device design specifically designed to cope with the challenges of implanting a stent graft very close to the coronary vessels, after accommodating severe angulations of the arch and extreme hemodynamic forces, is obvious. The configuration of standard thoracic endografts may cause disastrous complications, such as injury of the aortic valve or the left ventricle, by the long and inflexible introducer tips of standard endografts. The Zenith Ascend TAA Endovascular Graft with its soft, flexible tip and its controlled staged deployment has met many of these urgently needed modifications to serve the needs of the ascending aorta. In this series, we report a multicenter experience with the Ascend graft for a variety of indications. Given that open repair remains the standard of care for the ascending aorta in all participating institutions, the cases represent a negative selection with high technical difficulty and comorbid status that would alternatively be treated conservatively. The early results are promising, with a 30-day mortality of 10%; the single early death occurred in a patient who emergently received an Ascend aortic graft as a bailout procedure after intraoperative TAAD during complex transfemoral aortic valve repair. In that particular case, the graft was also undersized in comparison to the native aorta, thus not achieving proximal seal and resulting in clinical failure to exclude the dissection. The 10 patients studied in this paper were treated for a variety of indications and even included unusual indications, such as fixation of an aortic valve at the wall of the ascending aorta. The unusual and challenging indications could explain the early mortality and the need for reintervention as well as the graft infection in the cohort. Reinterventions in such a cohort of patients do not represent a treatment failure but rather the completion of the repair of a complex disease, which even when treated by open surgery would require additional management. Another key point that can be extrapolated by the present series is that in the absence of an adequate transfemoral approach, the transapical approach is a feasible alternative in these patients. It worked sufficiently with accurate graft deployment in two cases. Although an infrarenal or iliac conduit is also a good option in these patients, we would choose to avoid such an access in patients with residual dissection of the thoracoabdominal aorta. The transapical approach also allows more accurate stent graft positioning. The decision as to whether the access should be transfemoral, over iliac conduit, or transapical should be individualized after consideration of anticipated difficulties in the target zone and in the access region. In contrast to previous reports regarding endovascular repair of the ascending aorta, we have not found an oversizing of 20% or more to promote aortic valve
insufficiency.5 In contrast, we would strongly recommend at least 20% oversizing in native ascending aorta to avoid possible undersizing, especially in consideration of the variation of 15% in diameter observed in the native ascending aorta and arch during the cardiac cycle.25 Although traditionally a seal zone of at least 20 mm is required for aneurysms and dissections in the descending aorta, the use of the Ascend endovascular graft with its accurate, staged deployment mechanism could possibly enable successful treatment of pathologic processes even with a landing zone of 10 mm distal to the coronary orifices and a distal landing zone of at least 10 mm proximal to the innominate artery. The role of the Ascend graft in type A dissections still needs to be defined in larger series. Next to the proximal and distal landing zone, the diameter of the proximal landing zone should not exceed 38 mm or be below 24 mm. The length of the ascending aorta in the outer curvature should be at least 65 mm to accommodate the graft. In the case of an inadequate distal landing zone or a short length of the ascending aorta, it is possible to improve the distal landing zone by performing cervical debranching or extending the endovascular repair with fenestrated or branched arch endograft. Limitations. Major limitations of the study include the restricted sample size with 10 patients treated during a 4-year period and a restricted median follow-up of 10 months. Another major limitation is the variability of indications for treatment with the specific endograft and its compassionate use only, thus possibly not doing justice to the endograft’s performance. CONCLUSIONS Open repair of ascending aortic pathologic processes remains the “gold standard,” but its effectiveness is limited in high-risk patients, such as patients with prior cardiothoracic surgery or advanced age, because of the relevant perioperative morbidity and mortality. The present series provides encouraging evidence for the safety and feasibility of a device specific for treatment of ascending aortic diseases, although larger studies are required to confirm safety and to prove effectiveness of the stent graft. AUTHOR CONTRIBUTIONS Conception and design: NT, TK Analysis and interpretation: NT, ED, GO, SH, KT, BR, CD, TK Data collection: NT, GO, SH, KT, BR, CD, TK Writing the article: NT, TK Critical revision of the article: NT, ED, GO, SH, KT, BR, CD, TK Final approval of the article: NT, ED, GO, SH, KT, BR, CD, TK Statistical analysis: NT Obtained funding: Not applicable Overall responsibility: NT
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Submitted Sep 11, 2015; accepted Dec 15, 2015.
