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Simplified total aortic arch replacement with an in situ stent graft fenestration technique for acute type A aortic dissection
Simplified total aortic arch replacement with an in situ stent graft fenestration technique for acute type A aortic dissection Xiaoping Hu, MD, Zhiwei Wang, PhD, Zongli Ren, MD, Rui Hu, MD, and Hongbing Wu, MD, Wuhan, Hubei, P.R. China
ABSTRACT Objective: Total arch replacement combined with stented elephant trunk implantation in the descending aorta has successfully improved the outcomes of acute type A aortic dissection (AAAD). However, the optimal surgical strategy for the left subclavian artery (LSA) during the procedure remains a challenge. This study aimed to present our new technique of in situ stent graft fenestration to simplify the surgical procedure for suitable cases of AAAD. Methods: From August 2008 to December 2015, a total of 106 patients underwent simplified total aortic arch replacement with an in situ stent graft fenestration technique. The mean age of the patients was 50.71 6 11.54 years (range, 24-78 years). Both perioperative variables and postoperative follow-up outcome of the procedure were assessed. Results: The in-hospital mortality rate was 7.5%. The mean cardiopulmonary bypass time was 162.73 6 68.49 minutes, cross-clamp time was 93.13 6 22.29 minutes, and circulatory arrest time was 23.28 6 5.56 minutes. Transient neurologic dysfunction was observed in five patients. No permanent neurologic dysfunction was observed, and no stroke or left arm ischemia occurred. During the follow-up period (mean, 43.4 6 21.53 months), the survival rates of patients were 90.6%, 85.5%, and 78.8% at 1 year, 2 years, and 7 years, respectively. No stroke or left limb ischemia was observed. The LSA perfusion was well preserved in all surviving patients, and there was no endoleak or dissection around the LSA. All patients were free from reoperation. Conclusions: The in situ graft fenestration technique could simplify the procedure of LSA reconstruction during total arch replacement, provide a good surgical view for anastomosis and hemostasis, shorten the operation time, and yield satisfactory early and midterm results. It is a safe and effective alternative approach for suitable patients with AAAD. However, the long-term results of this technique need further evaluation. (J Vasc Surg 2017;-:1-7.)
Acute type A aortic dissection (AAAD) is a lethal condition with a 2-week survival rate of <20%.1 Presently, with advances in surgical techniques, the outcome of AAAD has improved significantly, but its morbidity and mortality rates are still high.2-4 Up to now, various surgical procedures have been used for AAAD, but the optimal procedure is still controversial. Conventional procedures have focused on replacement of the ascending aorta with or without hemiarch replacement. However, the prognosis is severely affected by the high rate of residual false lumen patency in the downstream aorta, and reoperation is not always likely to be avoided.5 Total arch replacement combined with stent elephant trunk implantation in the descending aorta presents satisfactory results. It could promote thrombosis in the false lumen, reduce the rate of false lumen patency, and decrease the rate of
reoperation accordingly.6 However, because of the deep surgical field of the distal aortic arch, total arch replacement combined with stent elephant trunk implantation has some disadvantages.7,8 First, left subclavian artery (LSA) anastomosis and distal anastomosis at the descending aorta are remarkably difficult to perform. Second, visualization and resolution of anastomotic leakage are difficult. Third, the incidence of superior laryngeal nerve injury and recurrent laryngeal nerve injury is high, and this induces bucking and hoarseness after surgery. Finally, the entire procedure is time-consuming. To address these disadvantages, we modified the procedure. Therefore, the purpose of this study was to present our new technique of in situ stent graft fenestration to simplify the surgical procedure for suitable cases of AAAD.
METHODS From the Department of Cardiovascular Surgery, Renmin Hospital of Wuhan University. Author conflict of interest: none. Correspondence: Zhiwei Wang, PhD, Department of Cardiovascular Surgery, Renmin Hospital of Wuhan University, Jiefang Rd 238, Wuchang District, Wuhan, Hubei 430060, P.R. China (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 2017 by the Society for Vascular Surgery. Published by Elsevier Inc. http://dx.doi.org/10.1016/j.jvs.2017.01.030
Patients. This study was approved by the Institutional Review Board of the Renmin Hospital of Wuhan University and was conducted in compliance with Health Insurance Portability and Accountability Act regulations and the Declaration of Helsinki. The Institutional Review Board waived the need for consent of individual patients. The inclusion criteria were as follows: surgery performed within 48 hours after acute onset; origin of the LSA localized in the true lumen; and absence of dissection within a 1.5-cm area around the LSA origin. Patients with Marfan 1
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syndrome, Ehlers-Danlos syndrome, a bicuspid aortic valve, or other known connective tissue disorders and those undergoing reoperation were excluded. None of the patients had dissection induced by trauma or cardiovascular surgery. In addition, patients who had received hemiarch replacement or traditional total arch replacement with stented elephant trunk implantation were excluded from this study. From August 2008 to December 2015 in our center, 220 consecutive patients with AAAD underwent total arch replacement combined with stented elephant trunk implantation. Among these patients, 106 patients underwent LSA revascularization using simplified total arch replacement with an in situ stent graft fenestration technique. Surgical procedures. All procedures in this study were performed under general anesthesia within 48 hours after acute onset by experienced surgeons and through a standard median sternotomy. Cardiopulmonary bypass (CPB) was established by cannulating the femoral artery and placing a dual-stage atriocaval cannula in the right atrium. The innominate artery, left common carotid artery, and LSA were exposed and dissected. The heart was arrested with perfusion of a cold blood cardioplegic solution after cross-clamping of the ascending aorta. During cooling, aortic root procedures, involving aortic valve replacement or aortic valve sparing, were performed according to the extent of aortic dissection and the pathologic status of the aortic valve. Systemic circulatory arrest was initiated on reaching a nasopharyngeal temperature of 20 C. The aortic arch was opened longitudinally. Bilateral antegrade cerebral perfusion was performed through the brachiocephalic trunk and left common carotid artery with a flow rate of 5 to 10 mL/kg/min under a pressure of 30 to 40 mm Hg. The aorta was opened longitudinally between the left common carotid artery and the LSA to explore any dissection at the three branches. When the origin of the LSA was localized in the true lumen and no dissection existed within a 1.5-cm area around the origin, the in situ stent graft fenestration technique was performed to simplify the procedure of total aortic arch replacement. The Chinese Cronus stented graft system (26-36 mm in diameter; MicroPort Medical Co, Ltd, Shanghai, China) was used in our surgical procedure. It consists of a woven Daron graft and a self-expandable metallic stent. The graft is longer than the stent and is used to cover the stent. Hence, there is a 10-mm stent-free sewing Dacron edge at each end of the system. The stent graft system was inserted into the true lumen of the descending aorta under direct visualization, with the self-expandable metallic stent completely covering the LSA. Subsequently, an electrosurgical scalpel was used to remove a patch of the polyester fabric of the stent graft proximal to the origin of the LSA to reconstruct the LSA (Fig 1). The diameter of the perforation at the stent graft was similar
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ARTICLE HIGHLIGHTS d
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Type of Research: Retrospective single-center cohort study Take Home Message: In 106 patients, a Dacron graft sewn to a stent graft elephant trunk with a left subclavian artery fenestration decreased circulatory arrest times and appeared to improve outcomes of patients. Recommendation: The authors suggest a novel technique to repair type A dissections with decreased circulatory arrest times and improved outcomes for patients.
to that of the LSA orifice. To avoid stent distortion and displacement, four stitches were placed to stabilize the orifice, and the proximal stent-free sewing Dacron edge was fixed to the aortic wall. Subsequently, the proximal end of the stented graft and aortic wall were anastomosed together to a four-branched prosthetic graft with 4-0 polypropylene sutures through continuous suturing (Figs 2 and 3). Antegrade systemic perfusion was then resumed through the perfusion limb of the four-branched prosthetic graft, followed by rewarming. During rewarming, the left common carotid artery and brachiocephalic trunk were anastomosed to the prosthetic graft individually. When all the arch vessels were reconstructed, proximal anastomosis of the ascending aorta was performed. Finally, the patient was weaned from CPB gradually, and then the chest was closed. Follow-up. Vascular ultrasound was performed to detect the blood supply of the LSA once per month for the first 6 months after the procedure. Computed tomography angiography (CTA) was scheduled for each patient before discharge, at month 6, and annually thereafter to detect thrombosis of the residual false lumen in the downstream aorta, endoleak, and malperfusion of the LSA. Statistical analysis. Data are expressed as mean 6 standard deviation for continuous variables and number (percentage) for discrete variables. The Kaplan-Meier method was used for the estimation of survival of the patients. Data analysis was performed using SPSS 19.0 (IBM Corp, Armonk, NY).
RESULTS Demographic and clinical characteristics. Table I summarizes the characteristics of the patients and procedure-related variables. All the patients (male, 69; female, 37; mean age, 50.71 6 11.54 years) underwent surgical intervention within 48 hours after clinical onset. Among the patients, 25 (23.6%) patients were diagnosed with hypoxemia, 77 (72.6%) with hypertension, and 57 (53.8%) with a history of smoking. According to the
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Fig 1. An electrosurgical scalpel was used to remove a patch of the polyester fabric of the stent graft proximal to the origin of the left subclavian artery (LSA) to reconstruct the LSA.
echocardiography findings, the left ventricular ejection fraction ranged from 40% to 60% (mean, 50.97% 6 3.41%). The numbers of patients with aortic regurgitation and mitral regurgitation were 45 (42.5%) and 10 (9.4%), respectively. Four patients (3.8%) showed impairment of renal function. Perioperative profiles. Thirty-three cases (31.13%) received Bentall procedures involving composite graft replacement of the aortic valve, aortic root, and ascending aorta, with reimplantation of the coronary arteries into the graft. Four cases (3.78%) underwent valve-sparing aortic root procedures. Ten (9.4%) patients with coronary artery malperfusion underwent coronary artery bypass graft with a saphenous vein graft. The most commonly involved coronary artery was the right coronary artery. Eight patients (7.5%) required mitral valve repair as the regurgitation was serious with no anatomic dysfunction, and two patients (1.88%) needed mitral valve replacement because of serious regurgitation with anatomic dysfunction. The CPB time was 162.73 6 68.49 minutes, crossclamp time was 93.13 6 22.29 minutes, and circulatory arrest time was 23.28 6 5.56 minutes. Eight patients (7.5%) died in the hospital, and among these patients, four died of multiple organ failure after the procedure, two died of acute renal failure, and two died of severe pulmonary infection. Transient neurologic dysfunction was observed in five patients, whereas no case of permanent neurologic dysfunction was noted. The mean intubation time was 19.19 6 8.3 hours, and intensive care unit stay was 77.37 6 37.53 hours. No case of stroke or left arm ischemia was noted. The postoperative results and complications are listed in Table II. Follow-up results. Follow-up of the patients was confirmed by a schedule of recent visits or by telephone, and follow-up was completed in 97.08% of surviving patients. The mean follow-up duration was 43.4 6 21.53 months (range, 3-88 months). The 1-year, 2-year, and 7-year survival rates were 90.6%, 85.5%, and 78.8%, respectively (Fig 4). The LSA showed satisfactory patency
Fig 2. The Chinese Cronus stent graft was inserted into the true lumen of the descending aorta under direct visualization, with the tubular material completely covering the left subclavian artery (LSA).
as revealed by vascular ultrasound. The CTA data of the first postoperative year showed that 100% of cases had complete thrombosis in the false lumen at the level of the proximal descending aorta, and 59.5% of cases had complete thrombosis at the diaphragmatic level. Only 10 patients showed false lumen patency. During the followup, the LSA of all surviving patients was confirmed to be patent without stenosis, endoleak, or dissection (Fig 5). No patient underwent reoperation.
DISCUSSION AAAD is a surgical emergency with high mortality and morbidity rates, despite the introduction of new surgical techniques and hybrid approaches. Total arch replacement combined with stented elephant trunk implantation has been used in the treatment of type A aortic dissection involving the aortic arch to improve the outcomes.9 However, this surgical procedure is complex with a long circulatory arrest time, which may increase the procedure-associated mortality and morbidity.10 Thus, simplification of the procedure and minimization of the circulatory arrest time can greatly improve the surgical outcome. During the procedure, anastomosis between the branch graft and the LSA is difficult, which may prolong the circulatory arrest time and lead to a high potential risk of anastomotic bleeding.11 The incidence of cerebral complications after the procedure has decreased with improvements in cerebral protective techniques including antegrade cerebral perfusion, retrograde cerebral perfusion, and hypothermia. However, the circulatory arrest time is still the main factor for decreasing surgery-associated complications, especially cerebral dysfunction. Many techniques have been developed to simplify the procedure and to reduce the circulatory arrest time, which may improve the outcome of the procedure. Previously, the triplebranched stent graft technique was used,12,13 which made the procedure easier and less time-consuming. However, anastomosis of aortic branches is difficult,
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Fig 3. Schematic drawing of the surgical procedure including aortic root procedure, total arch replacement combined with stented elephant trunk implantation, and in situ stent graft fenestration. Internal drainage: a chamber was created by wrapped around the proximal aortic graft with the dissected aortic wall or the autologous pericardium. The chamber was then made to communicate with the right atrium using prosthetic graft (8 mm in diameter). In this case, the hemorrhage from the aortic root was drained to the right atrium.
Table I. Clinical data Variable Age, years Gender, M/F
Values 24-78 years (50.71 6 11.54) 69/37
Hypertension
77 (72.6)
Smoking
57 (53.8)
LVEF, %
40-60 (50.97 6 3.41)
Hypoxemia
25 (23.6)
Aortic regurgitation
45 (42.5)
Mitral regurgitation
10 (9.4)
Cardiac tamponade
8 (7.5)
Coronary malperfusion
11 (10.4)
Renal dysfunction
4 (3.8)
LVEF, Left ventricular ejection fraction. Categorical variables are presented as number (%). Continuous variables are presented as mean 6 standard deviation.
which hampers the extensive application of this technique. Xiao et al14 promoted another technique to simplify the procedure, in which the LSA was ligated during total arch replacement and anastomosis was performed between the left axillary artery and one branch of a four-branched vascular graft within the first intercostal space. However, this technique resulted in an
increase in the circulatory arrest time (52.2 6 33.2 minutes) and showed a relatively high nosocomial mortality rate (18.2%). Thus, reducing the anastomotic time of the three aortic branches may lead to a decrease in the circulatory arrest time, which may improve the surgical outcomes. Anastomosis of the LSA is the most difficult approach in the deep surgical field, with a high incidence of anastomotic leakage. With our in situ stent graft fenestration technique, anastomosis of the LSA was simplified, and the circulatory arrest time was shorter in our study than in the study by Dias et al (23.28 6 5.56 minutes vs 40 6 8 minutes).15 In addition, the results of cerebral complication were encouraging as only five (4.7%) patients had transient neurologic dysfunction, and no permanent neurologic dysfunction occurred. The first in situ fenestration of the LSA during endovascular aortic arch repair was reported in 2004.16 This technique has several disadvantages for the repair of the endovascular aortic arch. First, there is no dedicated stent graft fabric to allow aeration of round and durable fenestrations by simple dilation of a puncture hole. Second, accurate puncture at the aortic stent graft is complex. However, this technique is not used during the surgical procedure. In our center, this technique has been used in patients with AAAD who underwent total
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Table II. Perioperative data Variables CPB time, minutes
Values 162.73 6 68.49
Cross-clamp time, minutes
93.13 6 22.29
Circulatory arrest time, minutes
23.28 6 5.56
Associated procedure Aortic valve replacement
4 (3.78)
David
4 (3.78)
Bentall
33 (31.13)
Cabrol
3 (2.8)
Mitral valve repair
8 (7.5)
CABG Intubation time, hours ICU stay, hours In-hospital mortality
10 (9.4) 19.19 6 8.3 77.37 6 37.53 8 (7.5)
Complications Re-exploration for bleeding
4 (3.78)
Transient neurologic dysfunction
5 (4.7)
Stroke
0
Left limb dysfunction
0
CABG, Coronary artery bypass graft; CPB, cardiopulmonary bypass; ICU, intensive care unit. Categorical variables are presented as number (%). Continuous variables are presented as mean 6 standard deviation.
Fig 4. Kaplan-Meier survival curve for the population of patients.
arch replacement combined with stented elephant trunk implantation. According to our clinical experience, fenestration was accurate and the puncture hole was round and durable under direct visualization. Actually, it is important for surgeons to measure the distance between the laceration and the LSA at aortic CTA. The distance between the laceration and the LSA should be >1.5 cm. During the procedure, the surgeon should reconfirm the distance before puncturing the stent graft. If the dissection flap involves the aortic wall within the 1.5-cm distance to the LSA origin, the technique should
Fig 5. Computed tomography scan confirmed the left subclavian artery (LSA) to be patent without stenosis, endoleak, or dissection.
be abandoned as there is a high chance of endoleak. In these patients, there was no endoleak, and LSA perfusion was good during the follow-up period. The size of the stent graft is another factor for the successful use of in situ fenestration in patients undergoing total arch replacement combined with stented elephant trunk implantation. The accurate size of the Chinese Cronus stent graft system contributed to the appropriate closing of the intimal tear in the true lumen. Meanwhile, it could gradually enlarge the true lumen vs shrink the false lumen.7,17,18 The distal artery can quickly restore normal blood flow. According to our experience, the size of a selected Cronus stent graft system should be 10% larger than the size of the true lumen. The most common size used is approximately 28 to 30 mm. The procedure of fenestration should be accurate to avoid injury to the LSA orifice. The diameter of the perforation at the stent graft was created similar to or slightly smaller than the diameter of the LSA orifice. To the best of our knowledge, reinforcement of the fenestration is important for the procedure. We reinforced the fenestration from three aspects. First, an accurately sized stent graft was selected. Considering the self-expansibility of the stent, the stent would closely attach to the aortic wall owing to radial stress.19 Second, according to the distance between the orifices of the left common carotid artery and LSA, the proximal stent-free sewing Dacron should be trimmed to eligible length to achieve ideal distal anastomosis. Then, the proximal stent-free sewing Dacron edge was fixed to the aortic wall. Subsequently, the proximal end of the stented graft and aortic wall were anastomosed together to a four-branched
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prosthetic graft. Third, four stitches were used to stabilize the orifice and the stent graft. In this case, the Cronus stent graft system in the descending aorta was fixed firmly. Stent distortion and displacement that may lead to LSA malperfusion and LSA orifice stenosis could be avoided. Nowadays, improved perioperative management and surgical techniques allow AAAD patients to overcome major complications, but the early postoperative outcomes remain less than satisfactory. The 30-day hospital mortality rate has been reported to be up to 20%.20,21 With the in situ graft fenestration technique, our hospital mortality rate was 7.5%. Previous studies describing late survival after AAAD reported 5-year survival rates of 72% to 79%,21,22 whereas our study revealed that the survival rates were 90.6%, 85.5%, and 78.8% at 1 year, 2 years, and 7 years, respectively. In our study, the causes of late mortality after acute type A dissection repair were cardiac failure in two patients, respiratory failure in one patient, myocardial infarction in one patient, aneurysm rupture in two patients, traffic accident in one patient, and unknown in three patients. During the follow-up period, no patient needed reintervention, and no patient had endoleak from the fenestration. Based on our experiences, selection of suitable patients and stent graft sizes are the key points in our simplified total aortic arch replacement with an in situ stent graft fenestration technique. Our simplified technique for AAAD had several advantages. First, the LSA was constructed with a relatively easy approach. Second, we performed distal aortic anastomosis between the left common carotid artery and the LSA, which provided a better surgical view for anastomosis and hemostasis and helped avoided injuries to the recurrent laryngeal and phrenic nerves. Finally, short operation, CPB, and circulatory arrest times were obtained, which contributed to the lower incidence of neurologic dysfunction and fewer operative injuries. This study has some limitations. We analyzed the fenestration cases retrospectively, and nonfenestration cases were not included. In the future, studies with a longterm follow-up and randomization should be performed to compare fenestration and nonfenestration cases, and the findings of these studies will provide precise conclusions on the use of such a procedure for AAAD.
CONCLUSIONS The in situ graft fenestration technique could simplify the procedure of LSA reconstruction during total arch replacement, provide a good surgical view for anastomosis and hemostasis, shorten the operation time, and yield satisfactory early and midterm results. It is a safe and effective alternative approach for suitable patients with AAAD. However, the long-term results of this technique need further evaluation.
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AUTHOR CONTRIBUTIONS Conception and design: XH, ZW Analysis and interpretation: XH, ZW, ZR, RH, HW Data collection: XH, ZW, ZR, RH, HW Writing the article: XH Critical revision of the article: XH, ZW, ZR, RH, HW Final approval of the article: XH, ZW, ZR, RH, HW Statistical analysis: XH, ZW, ZR, RH, HW Obtained funding: Not applicable Overall responsibility: XH
REFERENCES 1. Coady MA, Rizzo JA, Goldstein LJ, Elefteriades JA. Natural history, pathogenesis, and etiology of thoracic aortic aneurysms and dissections. Cardiol Clin 1999;17:615-35. 2. Hata M, Sezai A, Yoshitake I, Wakui S, Takasaka A, Minami K, et al. Clinical trends in optimal treatment strategy for type A acute aortic dissection. Ann Thorac Cardiovasc Surg 2010;16: 228-35. 3. Trimarchi S, Nienaber CA, Rampoldi V, Myrmel T, Suzuki T, Mehta RH, et al. Contemporary results of surgery in acute type A aortic dissection: the International Registry of Acute Aortic Dissection experience. J Thorac Cardiovasc Surg 2005;129:112-22. 4. Hagl C, Khaladj N, Peterss S, Bonz A, Pichlmaier M, Haverich A, et al. Treatment of acute aortic dissection type A (AADA): technical considerations. Vasa 2010;39:212-8. 5. Song SW, Chang BC, Cho BK, Yi G, Youn YN, Lee S, et al. Effects of partial thrombosis on distal aorta after repair of acute DeBakey type I aortic dissection. J Thorac Cardiovasc Surg 2010;139:841-7. 6. 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 2011;123:971-8. 7. Liu ZG, Sun LZ, Chang Q, Zhu JM, Dong C, Yu CT, et al. Should the “elephant trunk” be skeletonized? Total arch replacement combined with stented elephant trunk implantation for Stanford type A aortic dissection. J Thorac Cardiovasc Surg 2006;131:107-13. 8. Chen LW, Dai XF, Yang GF, Zhang GC, Cao H, Wang QM. Open-branched stent graft placement makes total arch replacement easier for acute type A aortic dissection. Ann Thorac Surg 2010;89:1688-90. 9. Dobrilovic N, Elefteriades JA. Stenting the descending aorta during repair of type A dissection: technology looking for an application? J Thorac Cardiovasc Surg 2006;131:777-8. 10. Hiratzka LF, Bakris GL, Beckman JA, Bersin RM, Carr VF, Casey DJ, et al. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/ SIR/STS/SVM guidelines for the diagnosis and management of patients with thoracic aortic disease. A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, The Society of Thoracic Surgeons, and Society for Vascular Medicine. J Am Coll Cardiol 2010;55:e27-129. 11. Mori Y, Hirose H, Takagi H, Umeda Y, Fukumoto Y, Shimabukuro K, et al. Aortic arch repair for Stanford type A aortic dissection with distal anastomosis to the proximal level of the distal aortic arch. J Thorac Cardiovasc Surg 2003;126:415-9.
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12. Chen LW, Dai XF, Lu L, Zhang GC, Cao H. Extensive primary repair of the thoracic aorta in acute type A aortic dissection by means of ascending aorta replacement combined with open placement of triple-branched stent graft: early results. Circulation 2010;122:1373-8. 13. Shen K, Tang H, Jing R, Liu F, Zhou X. Application of triplebranched stent graft for Stanford type A aortic dissection: potential risks. Eur J Cardiothorac Surg 2012;41:e12-7. 14. Sepehripour AH, Ahmed K, Vecht JA, Anagnostakou V, Suliman A, Ashrafian H, et al. Management of the left subclavian artery during endovascular stent grafting for traumatic aortic injury: a systematic review. Eur J Vasc Endovasc Surg 2011;41:758-69. 15. Dias R, Duncan JA, Vianna DS, de Faria LB, Fernandes F, Ramirez FJ, et al. Surgical treatment of complex aneurysms and thoracic aortic dissections with the Frozen Elephant Trunk technique. Rev Bras Cir Cardiovasc 2015;30: 205-10. 16. McWilliams RG, Murphy M, Hartley D, Lawrence-Brown MM, Harris PL. In situ stent-graft fenestration to preserve the left subclavian artery. J Endovasc Ther 2004;11:170-4. 17. Sun L, Qi R, Chang Q, Zhu J, Liu Y, Yu C, et al. Surgery for acute type A dissection with the tear in the descending aorta
using a stented elephant trunk procedure. Ann Thorac Surg 2009;87:1177-80. 18. Sun LZ, Qi RD, Chang Q, Zhu JM, Liu YM, Yu CT, et al. Surgery for acute type A dissection using total arch replacement combined with stented elephant trunk implantation: experience with 107 patients. J Thorac Cardiovasc Surg 2009;138: 1358-62. 19. Gao F, Guo Z, Sakamoto M, Matsuzawa T. Fluid-structure interaction within a layered aortic arch model. J Biol Phys 2006;32:435-54. 20. Chavanon O, Costache V, Bach V, Ketata A, Durand M, Hacini R, et al. Preoperative predictive factors for mortality in acute type A aortic dissection: an institutional report on 217 consecutives cases. Interact Cardiovasc Thorac Surg 2007;6:43-6. 21. Pagni S, Ganzel BL, Trivedi JR, Singh R, Mascio CE, Austin EH, et al. Early and midterm outcomes following surgery for acute type A aortic dissection. J Card Surg 2013;28:543-9. 22. Numata S, Tsutsumi Y, Monta O, Yamazaki S, Seo H, Yoshida S, et al. Mid-long-term results after aortic arch repair using a four-branched graft with antegrade selective cerebral perfusion. J Card Surg 2013;28:537-42. Submitted Jul 31, 2016; accepted Jan 12, 2017.
ABSTRACT Objective: Total arch replacement combined with stented elephant trunk implantation in the descending aorta has successfully improved the outcomes of acute type A aortic dissection (AAAD). However, the optimal surgical strategy for the left subclavian artery (LSA) during the procedure remains a challenge. This study aimed to present our new technique of in situ stent graft fenestration to simplify the surgical procedure for suitable cases of AAAD. Methods: From August 2008 to December 2015, a total of 106 patients underwent simplified total aortic arch replacement with an in situ stent graft fenestration technique. The mean age of the patients was 50.71 6 11.54 years (range, 24-78 years). Both perioperative variables and postoperative follow-up outcome of the procedure were assessed. Results: The in-hospital mortality rate was 7.5%. The mean cardiopulmonary bypass time was 162.73 6 68.49 minutes, cross-clamp time was 93.13 6 22.29 minutes, and circulatory arrest time was 23.28 6 5.56 minutes. Transient neurologic dysfunction was observed in five patients. No permanent neurologic dysfunction was observed, and no stroke or left arm ischemia occurred. During the follow-up period (mean, 43.4 6 21.53 months), the survival rates of patients were 90.6%, 85.5%, and 78.8% at 1 year, 2 years, and 7 years, respectively. No stroke or left limb ischemia was observed. The LSA perfusion was well preserved in all surviving patients, and there was no endoleak or dissection around the LSA. All patients were free from reoperation. Conclusions: The in situ graft fenestration technique could simplify the procedure of LSA reconstruction during total arch replacement, provide a good surgical view for anastomosis and hemostasis, shorten the operation time, and yield satisfactory early and midterm results. It is a safe and effective alternative approach for suitable patients with AAAD. However, the long-term results of this technique need further evaluation. (J Vasc Surg 2017;-:1-7.)
Acute type A aortic dissection (AAAD) is a lethal condition with a 2-week survival rate of <20%.1 Presently, with advances in surgical techniques, the outcome of AAAD has improved significantly, but its morbidity and mortality rates are still high.2-4 Up to now, various surgical procedures have been used for AAAD, but the optimal procedure is still controversial. Conventional procedures have focused on replacement of the ascending aorta with or without hemiarch replacement. However, the prognosis is severely affected by the high rate of residual false lumen patency in the downstream aorta, and reoperation is not always likely to be avoided.5 Total arch replacement combined with stent elephant trunk implantation in the descending aorta presents satisfactory results. It could promote thrombosis in the false lumen, reduce the rate of false lumen patency, and decrease the rate of
reoperation accordingly.6 However, because of the deep surgical field of the distal aortic arch, total arch replacement combined with stent elephant trunk implantation has some disadvantages.7,8 First, left subclavian artery (LSA) anastomosis and distal anastomosis at the descending aorta are remarkably difficult to perform. Second, visualization and resolution of anastomotic leakage are difficult. Third, the incidence of superior laryngeal nerve injury and recurrent laryngeal nerve injury is high, and this induces bucking and hoarseness after surgery. Finally, the entire procedure is time-consuming. To address these disadvantages, we modified the procedure. Therefore, the purpose of this study was to present our new technique of in situ stent graft fenestration to simplify the surgical procedure for suitable cases of AAAD.
METHODS From the Department of Cardiovascular Surgery, Renmin Hospital of Wuhan University. Author conflict of interest: none. Correspondence: Zhiwei Wang, PhD, Department of Cardiovascular Surgery, Renmin Hospital of Wuhan University, Jiefang Rd 238, Wuchang District, Wuhan, Hubei 430060, P.R. China (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 2017 by the Society for Vascular Surgery. Published by Elsevier Inc. http://dx.doi.org/10.1016/j.jvs.2017.01.030
Patients. This study was approved by the Institutional Review Board of the Renmin Hospital of Wuhan University and was conducted in compliance with Health Insurance Portability and Accountability Act regulations and the Declaration of Helsinki. The Institutional Review Board waived the need for consent of individual patients. The inclusion criteria were as follows: surgery performed within 48 hours after acute onset; origin of the LSA localized in the true lumen; and absence of dissection within a 1.5-cm area around the LSA origin. Patients with Marfan 1
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syndrome, Ehlers-Danlos syndrome, a bicuspid aortic valve, or other known connective tissue disorders and those undergoing reoperation were excluded. None of the patients had dissection induced by trauma or cardiovascular surgery. In addition, patients who had received hemiarch replacement or traditional total arch replacement with stented elephant trunk implantation were excluded from this study. From August 2008 to December 2015 in our center, 220 consecutive patients with AAAD underwent total arch replacement combined with stented elephant trunk implantation. Among these patients, 106 patients underwent LSA revascularization using simplified total arch replacement with an in situ stent graft fenestration technique. Surgical procedures. All procedures in this study were performed under general anesthesia within 48 hours after acute onset by experienced surgeons and through a standard median sternotomy. Cardiopulmonary bypass (CPB) was established by cannulating the femoral artery and placing a dual-stage atriocaval cannula in the right atrium. The innominate artery, left common carotid artery, and LSA were exposed and dissected. The heart was arrested with perfusion of a cold blood cardioplegic solution after cross-clamping of the ascending aorta. During cooling, aortic root procedures, involving aortic valve replacement or aortic valve sparing, were performed according to the extent of aortic dissection and the pathologic status of the aortic valve. Systemic circulatory arrest was initiated on reaching a nasopharyngeal temperature of 20 C. The aortic arch was opened longitudinally. Bilateral antegrade cerebral perfusion was performed through the brachiocephalic trunk and left common carotid artery with a flow rate of 5 to 10 mL/kg/min under a pressure of 30 to 40 mm Hg. The aorta was opened longitudinally between the left common carotid artery and the LSA to explore any dissection at the three branches. When the origin of the LSA was localized in the true lumen and no dissection existed within a 1.5-cm area around the origin, the in situ stent graft fenestration technique was performed to simplify the procedure of total aortic arch replacement. The Chinese Cronus stented graft system (26-36 mm in diameter; MicroPort Medical Co, Ltd, Shanghai, China) was used in our surgical procedure. It consists of a woven Daron graft and a self-expandable metallic stent. The graft is longer than the stent and is used to cover the stent. Hence, there is a 10-mm stent-free sewing Dacron edge at each end of the system. The stent graft system was inserted into the true lumen of the descending aorta under direct visualization, with the self-expandable metallic stent completely covering the LSA. Subsequently, an electrosurgical scalpel was used to remove a patch of the polyester fabric of the stent graft proximal to the origin of the LSA to reconstruct the LSA (Fig 1). The diameter of the perforation at the stent graft was similar
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ARTICLE HIGHLIGHTS d
d
d
Type of Research: Retrospective single-center cohort study Take Home Message: In 106 patients, a Dacron graft sewn to a stent graft elephant trunk with a left subclavian artery fenestration decreased circulatory arrest times and appeared to improve outcomes of patients. Recommendation: The authors suggest a novel technique to repair type A dissections with decreased circulatory arrest times and improved outcomes for patients.
to that of the LSA orifice. To avoid stent distortion and displacement, four stitches were placed to stabilize the orifice, and the proximal stent-free sewing Dacron edge was fixed to the aortic wall. Subsequently, the proximal end of the stented graft and aortic wall were anastomosed together to a four-branched prosthetic graft with 4-0 polypropylene sutures through continuous suturing (Figs 2 and 3). Antegrade systemic perfusion was then resumed through the perfusion limb of the four-branched prosthetic graft, followed by rewarming. During rewarming, the left common carotid artery and brachiocephalic trunk were anastomosed to the prosthetic graft individually. When all the arch vessels were reconstructed, proximal anastomosis of the ascending aorta was performed. Finally, the patient was weaned from CPB gradually, and then the chest was closed. Follow-up. Vascular ultrasound was performed to detect the blood supply of the LSA once per month for the first 6 months after the procedure. Computed tomography angiography (CTA) was scheduled for each patient before discharge, at month 6, and annually thereafter to detect thrombosis of the residual false lumen in the downstream aorta, endoleak, and malperfusion of the LSA. Statistical analysis. Data are expressed as mean 6 standard deviation for continuous variables and number (percentage) for discrete variables. The Kaplan-Meier method was used for the estimation of survival of the patients. Data analysis was performed using SPSS 19.0 (IBM Corp, Armonk, NY).
RESULTS Demographic and clinical characteristics. Table I summarizes the characteristics of the patients and procedure-related variables. All the patients (male, 69; female, 37; mean age, 50.71 6 11.54 years) underwent surgical intervention within 48 hours after clinical onset. Among the patients, 25 (23.6%) patients were diagnosed with hypoxemia, 77 (72.6%) with hypertension, and 57 (53.8%) with a history of smoking. According to the
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Fig 1. An electrosurgical scalpel was used to remove a patch of the polyester fabric of the stent graft proximal to the origin of the left subclavian artery (LSA) to reconstruct the LSA.
echocardiography findings, the left ventricular ejection fraction ranged from 40% to 60% (mean, 50.97% 6 3.41%). The numbers of patients with aortic regurgitation and mitral regurgitation were 45 (42.5%) and 10 (9.4%), respectively. Four patients (3.8%) showed impairment of renal function. Perioperative profiles. Thirty-three cases (31.13%) received Bentall procedures involving composite graft replacement of the aortic valve, aortic root, and ascending aorta, with reimplantation of the coronary arteries into the graft. Four cases (3.78%) underwent valve-sparing aortic root procedures. Ten (9.4%) patients with coronary artery malperfusion underwent coronary artery bypass graft with a saphenous vein graft. The most commonly involved coronary artery was the right coronary artery. Eight patients (7.5%) required mitral valve repair as the regurgitation was serious with no anatomic dysfunction, and two patients (1.88%) needed mitral valve replacement because of serious regurgitation with anatomic dysfunction. The CPB time was 162.73 6 68.49 minutes, crossclamp time was 93.13 6 22.29 minutes, and circulatory arrest time was 23.28 6 5.56 minutes. Eight patients (7.5%) died in the hospital, and among these patients, four died of multiple organ failure after the procedure, two died of acute renal failure, and two died of severe pulmonary infection. Transient neurologic dysfunction was observed in five patients, whereas no case of permanent neurologic dysfunction was noted. The mean intubation time was 19.19 6 8.3 hours, and intensive care unit stay was 77.37 6 37.53 hours. No case of stroke or left arm ischemia was noted. The postoperative results and complications are listed in Table II. Follow-up results. Follow-up of the patients was confirmed by a schedule of recent visits or by telephone, and follow-up was completed in 97.08% of surviving patients. The mean follow-up duration was 43.4 6 21.53 months (range, 3-88 months). The 1-year, 2-year, and 7-year survival rates were 90.6%, 85.5%, and 78.8%, respectively (Fig 4). The LSA showed satisfactory patency
Fig 2. The Chinese Cronus stent graft was inserted into the true lumen of the descending aorta under direct visualization, with the tubular material completely covering the left subclavian artery (LSA).
as revealed by vascular ultrasound. The CTA data of the first postoperative year showed that 100% of cases had complete thrombosis in the false lumen at the level of the proximal descending aorta, and 59.5% of cases had complete thrombosis at the diaphragmatic level. Only 10 patients showed false lumen patency. During the followup, the LSA of all surviving patients was confirmed to be patent without stenosis, endoleak, or dissection (Fig 5). No patient underwent reoperation.
DISCUSSION AAAD is a surgical emergency with high mortality and morbidity rates, despite the introduction of new surgical techniques and hybrid approaches. Total arch replacement combined with stented elephant trunk implantation has been used in the treatment of type A aortic dissection involving the aortic arch to improve the outcomes.9 However, this surgical procedure is complex with a long circulatory arrest time, which may increase the procedure-associated mortality and morbidity.10 Thus, simplification of the procedure and minimization of the circulatory arrest time can greatly improve the surgical outcome. During the procedure, anastomosis between the branch graft and the LSA is difficult, which may prolong the circulatory arrest time and lead to a high potential risk of anastomotic bleeding.11 The incidence of cerebral complications after the procedure has decreased with improvements in cerebral protective techniques including antegrade cerebral perfusion, retrograde cerebral perfusion, and hypothermia. However, the circulatory arrest time is still the main factor for decreasing surgery-associated complications, especially cerebral dysfunction. Many techniques have been developed to simplify the procedure and to reduce the circulatory arrest time, which may improve the outcome of the procedure. Previously, the triplebranched stent graft technique was used,12,13 which made the procedure easier and less time-consuming. However, anastomosis of aortic branches is difficult,
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Fig 3. Schematic drawing of the surgical procedure including aortic root procedure, total arch replacement combined with stented elephant trunk implantation, and in situ stent graft fenestration. Internal drainage: a chamber was created by wrapped around the proximal aortic graft with the dissected aortic wall or the autologous pericardium. The chamber was then made to communicate with the right atrium using prosthetic graft (8 mm in diameter). In this case, the hemorrhage from the aortic root was drained to the right atrium.
Table I. Clinical data Variable Age, years Gender, M/F
Values 24-78 years (50.71 6 11.54) 69/37
Hypertension
77 (72.6)
Smoking
57 (53.8)
LVEF, %
40-60 (50.97 6 3.41)
Hypoxemia
25 (23.6)
Aortic regurgitation
45 (42.5)
Mitral regurgitation
10 (9.4)
Cardiac tamponade
8 (7.5)
Coronary malperfusion
11 (10.4)
Renal dysfunction
4 (3.8)
LVEF, Left ventricular ejection fraction. Categorical variables are presented as number (%). Continuous variables are presented as mean 6 standard deviation.
which hampers the extensive application of this technique. Xiao et al14 promoted another technique to simplify the procedure, in which the LSA was ligated during total arch replacement and anastomosis was performed between the left axillary artery and one branch of a four-branched vascular graft within the first intercostal space. However, this technique resulted in an
increase in the circulatory arrest time (52.2 6 33.2 minutes) and showed a relatively high nosocomial mortality rate (18.2%). Thus, reducing the anastomotic time of the three aortic branches may lead to a decrease in the circulatory arrest time, which may improve the surgical outcomes. Anastomosis of the LSA is the most difficult approach in the deep surgical field, with a high incidence of anastomotic leakage. With our in situ stent graft fenestration technique, anastomosis of the LSA was simplified, and the circulatory arrest time was shorter in our study than in the study by Dias et al (23.28 6 5.56 minutes vs 40 6 8 minutes).15 In addition, the results of cerebral complication were encouraging as only five (4.7%) patients had transient neurologic dysfunction, and no permanent neurologic dysfunction occurred. The first in situ fenestration of the LSA during endovascular aortic arch repair was reported in 2004.16 This technique has several disadvantages for the repair of the endovascular aortic arch. First, there is no dedicated stent graft fabric to allow aeration of round and durable fenestrations by simple dilation of a puncture hole. Second, accurate puncture at the aortic stent graft is complex. However, this technique is not used during the surgical procedure. In our center, this technique has been used in patients with AAAD who underwent total
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Table II. Perioperative data Variables CPB time, minutes
Values 162.73 6 68.49
Cross-clamp time, minutes
93.13 6 22.29
Circulatory arrest time, minutes
23.28 6 5.56
Associated procedure Aortic valve replacement
4 (3.78)
David
4 (3.78)
Bentall
33 (31.13)
Cabrol
3 (2.8)
Mitral valve repair
8 (7.5)
CABG Intubation time, hours ICU stay, hours In-hospital mortality
10 (9.4) 19.19 6 8.3 77.37 6 37.53 8 (7.5)
Complications Re-exploration for bleeding
4 (3.78)
Transient neurologic dysfunction
5 (4.7)
Stroke
0
Left limb dysfunction
0
CABG, Coronary artery bypass graft; CPB, cardiopulmonary bypass; ICU, intensive care unit. Categorical variables are presented as number (%). Continuous variables are presented as mean 6 standard deviation.
Fig 4. Kaplan-Meier survival curve for the population of patients.
arch replacement combined with stented elephant trunk implantation. According to our clinical experience, fenestration was accurate and the puncture hole was round and durable under direct visualization. Actually, it is important for surgeons to measure the distance between the laceration and the LSA at aortic CTA. The distance between the laceration and the LSA should be >1.5 cm. During the procedure, the surgeon should reconfirm the distance before puncturing the stent graft. If the dissection flap involves the aortic wall within the 1.5-cm distance to the LSA origin, the technique should
Fig 5. Computed tomography scan confirmed the left subclavian artery (LSA) to be patent without stenosis, endoleak, or dissection.
be abandoned as there is a high chance of endoleak. In these patients, there was no endoleak, and LSA perfusion was good during the follow-up period. The size of the stent graft is another factor for the successful use of in situ fenestration in patients undergoing total arch replacement combined with stented elephant trunk implantation. The accurate size of the Chinese Cronus stent graft system contributed to the appropriate closing of the intimal tear in the true lumen. Meanwhile, it could gradually enlarge the true lumen vs shrink the false lumen.7,17,18 The distal artery can quickly restore normal blood flow. According to our experience, the size of a selected Cronus stent graft system should be 10% larger than the size of the true lumen. The most common size used is approximately 28 to 30 mm. The procedure of fenestration should be accurate to avoid injury to the LSA orifice. The diameter of the perforation at the stent graft was created similar to or slightly smaller than the diameter of the LSA orifice. To the best of our knowledge, reinforcement of the fenestration is important for the procedure. We reinforced the fenestration from three aspects. First, an accurately sized stent graft was selected. Considering the self-expansibility of the stent, the stent would closely attach to the aortic wall owing to radial stress.19 Second, according to the distance between the orifices of the left common carotid artery and LSA, the proximal stent-free sewing Dacron should be trimmed to eligible length to achieve ideal distal anastomosis. Then, the proximal stent-free sewing Dacron edge was fixed to the aortic wall. Subsequently, the proximal end of the stented graft and aortic wall were anastomosed together to a four-branched
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prosthetic graft. Third, four stitches were used to stabilize the orifice and the stent graft. In this case, the Cronus stent graft system in the descending aorta was fixed firmly. Stent distortion and displacement that may lead to LSA malperfusion and LSA orifice stenosis could be avoided. Nowadays, improved perioperative management and surgical techniques allow AAAD patients to overcome major complications, but the early postoperative outcomes remain less than satisfactory. The 30-day hospital mortality rate has been reported to be up to 20%.20,21 With the in situ graft fenestration technique, our hospital mortality rate was 7.5%. Previous studies describing late survival after AAAD reported 5-year survival rates of 72% to 79%,21,22 whereas our study revealed that the survival rates were 90.6%, 85.5%, and 78.8% at 1 year, 2 years, and 7 years, respectively. In our study, the causes of late mortality after acute type A dissection repair were cardiac failure in two patients, respiratory failure in one patient, myocardial infarction in one patient, aneurysm rupture in two patients, traffic accident in one patient, and unknown in three patients. During the follow-up period, no patient needed reintervention, and no patient had endoleak from the fenestration. Based on our experiences, selection of suitable patients and stent graft sizes are the key points in our simplified total aortic arch replacement with an in situ stent graft fenestration technique. Our simplified technique for AAAD had several advantages. First, the LSA was constructed with a relatively easy approach. Second, we performed distal aortic anastomosis between the left common carotid artery and the LSA, which provided a better surgical view for anastomosis and hemostasis and helped avoided injuries to the recurrent laryngeal and phrenic nerves. Finally, short operation, CPB, and circulatory arrest times were obtained, which contributed to the lower incidence of neurologic dysfunction and fewer operative injuries. This study has some limitations. We analyzed the fenestration cases retrospectively, and nonfenestration cases were not included. In the future, studies with a longterm follow-up and randomization should be performed to compare fenestration and nonfenestration cases, and the findings of these studies will provide precise conclusions on the use of such a procedure for AAAD.
CONCLUSIONS The in situ graft fenestration technique could simplify the procedure of LSA reconstruction during total arch replacement, provide a good surgical view for anastomosis and hemostasis, shorten the operation time, and yield satisfactory early and midterm results. It is a safe and effective alternative approach for suitable patients with AAAD. However, the long-term results of this technique need further evaluation.
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AUTHOR CONTRIBUTIONS Conception and design: XH, ZW Analysis and interpretation: XH, ZW, ZR, RH, HW Data collection: XH, ZW, ZR, RH, HW Writing the article: XH Critical revision of the article: XH, ZW, ZR, RH, HW Final approval of the article: XH, ZW, ZR, RH, HW Statistical analysis: XH, ZW, ZR, RH, HW Obtained funding: Not applicable Overall responsibility: XH
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