European Journal of Cardio-Thoracic Surgery Advance Access published July 11, 2015
ORIGINAL ARTICLE
European Journal of Cardio-Thoracic Surgery (2015) 1–5 doi:10.1093/ejcts/ezv242
Repair of complicated type B dissection with an isolated left vertebral artery using the stented elephant trunk technique Jun-Ming Zhu, Rui-Dong Qi, Yong-Min Liu, Jun Zheng, Xiao-Yan Xing and Li-Zhong Sun* Beijing Aortic Disease Center, Beijing Institute of Heart, Lung and Blood Vessel Diseases & Beijing Anzhen Hospital, Capital Medical University, Beijing, China * Corresponding author. Beijing Aortic Disease Center, Beijing Anzhen Hospital, Capital Medical University, 2 Anzhen Road, Beijing 100029, China. Tel: +86-10-64456168; fax: +86-10-64456168; e-mail: [email protected] (L.-Z. Sun). Received 17 March 2015; received in revised form 30 May 2015; accepted 15 June 2015
Abstract OBJECTIVES: The presence of an isolated left vertebral artery (ILVA) remains a challenging issue for thoracic endovascular aortic repair (TEVAR) of type B dissection if the proximal landing zones are inadequate. We retrospectively reviewed our experience of the surgical management of complicated type B dissection with an ILVA using the stented elephant trunk technique. METHODS: Between February 2009 and May 2013, 7 patients with complicated type B dissection (acute = 2 and chronic = 5) underwent the stented elephant trunk procedure under hypothermic cardiopulmonary bypass with selective antegrade cerebral perfusion. All the patients were males with a median age of 53 ± 6 (range 42–59) years. Preoperative lower limb ischaemia was observed in 1 patient, renal dysfunction in 1 patient and visceral ischaemia in 1 patient. RESULTS: There were no in-hospital deaths. The median ventilator support time was 16 ± 3 (range 11–20) h. Ischaemia of the lower limb and viscera was ameliorated after surgical stent-graft implantation. Continuous renal replacement therapy was not required in patients with preoperative renal dysfunction after surgery. No neurological deficits were observed in any patients prior to hospital discharge. One patient underwent TEVAR due to distal aortic dilatation within the mean follow-up period, which was 44 ± 19 months. CONCLUSION: Repair of complicated type B dissection with an ILVA using the stented elephant trunk technique was associated with satisfactory surgical results in patients with inadequate proximal fixation zones. This technique is an alternative to TEVAR for complicated type B dissection with inadequate proximal landing zones. Keywords: Type B dissection • Stented elephant trunk technique • Isolated left vertebral artery
INTRODUCTION
METHODS
An isolated left vertebral artery (ILVA), which arises directly from the aortic arch, is not uncommon among aortic arch vessel anomalies. The presence of an ILVA has considerable impact on the choice of aortic arch reconstruction techniques and cerebral protection methods in patients with aortic arch lesions. Improper management of the ILVA may result in ischaemia or infarction of the brain if the arterial circle of Willis is incomplete [1, 2]. In patients with type A dissection with an ILVA, total arch replacement using the separated graft technique was described in detail in our previous report [3]. In patients with an inadequate proximal landing zone, complicated type B dissection with an ILVA can be challenging for thoracic endovascular aortic repair (TEVAR). During TEVAR, coverage and revascularization of the left subclavian artery (LSCA) in patients with type B dissection with an ILVA have been reported [4]. In this study, we reviewed our experience with the surgical treatment of complicated type B dissection with an ILVA and inadequate proximal landing zones, using the stented elephant trunk technique.
Patients Between February 2009 and May 2013, 7 patients with complicated type B dissection and an ILVA (Fig. 1) underwent surgical treatment using a stented elephant trunk procedure under hypothermic cardiopulmonary bypass (CPB) with selective antegrade cerebral perfusion (SACP) at Beijing Aortic Disease Center, Beijing Anzhen Hospital. This technique was approved by the institutional review board of Capital Medical University. The mean age of our patient cohort was 53 ± 6 (range 42–59) years; all patients were male. The mean interval between the onset of aortic dissection and surgery was 42 ± 34 (range, 10–110) days. Two patients underwent surgery during the acute stage (within 2 weeks of symptom onset). Aortic dissection was confirmed prior to surgery by computed tomography (CT). Six patients had a history of hypertension; a failed prior TEVAR was present in 1 patient. In this group, type B dissection was complicated by uncontrolled
© The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
AORTIC SURGERY
Cite this article as: Zhu J-M, Qi R-D, Liu Y-M, Zheng J, Xing X-Y, Sun L-Z. Repair of complicated type B dissection with an isolated left vertebral artery using the stented elephant trunk technique. Eur J Cardiothorac Surg 2015; doi:10.1093/ejcts/ezv242.
J.-M. Zhu et al. / European Journal of Cardio-Thoracic Surgery
2
Figure 1: Preoperative computed tomography images of a patient with type B dissection with an ILVA. ILVA: isolated left vertebral artery; FL: false lumen; LSCA: left subclavian artery; TL: true lumen. The ILVA was involved by the dissection (A–C).
Table 1: Clinical profiles of patients with type B dissection with the ILVA No.
Age
Sex
Acuity
Symptoms and findings
Location of the primary tear
Distal arch involvement
Concomitant procedure
Complication
Follow-up
1
55
M
C
Uncontrolled HT
LSCA
AA–LSCA bypass
No
Alive
2
48
M
C
Uncontrolled HT
No
TEVAR
3
56
M
C
Lower limb ischaemia
4
59
M
C
5
59
M
A
Failure of TEVAR/persistent pain HT/persistent pain
6
53
M
A
HT/visceral ischaemia
7
42
M
C
Previous TEVAR/HT/DB/CAD/ renal dysfunction
Adjacent to the LSCAO Adjacent to the LSCAO Adjacent to the LSCAO Adjacent to the LSCAO Adjacent to the LSCAO Adjacent to the LSCAO Distal to the LSCAO
LSCA
LSCA–LCCA transposition
No
Alive
LSCA
LSCA–LCCA/ILVA–LSCA transposition LSCA–LCCA /ILVA–LSCA transposition LSCA–LCCA/ILVA–LCCA transposition
No
Alive
No
Alive
No
Alive
No
Alive
LSCA LSCAO
HT: hypertension; AA: ascending aorta; LSCA: left subclavian artery; LSCAO: left subclavian artery origin; LCCA: left common carotid artery; ILVA: isolated left vertebral artery; DB: diabetes mellitus; CAD: coronary artery disease; TEVAR: thoracic endovascular aortic repair.
hypertension in 2 patients, persistent pain in 2 patients, lower limb ischaemia in 1 patient, visceral ischaemia in 1 patient and renal dysfunction in 1 patient. Preoperative complications were common (Table 1). The primary tear was located near the origin of the LSCA in 6 patients and distal to the origin of the LSCA in the subject with the failed prior TEVAR. Involvement of the LSCA origin was present in 5 patients and involvement of the ILVA origin in 3. The dissection extended into the abdominal aorta in 3 cases and into the iliac artery in 4 cases. Postoperative CT and echocardiography were recommended to be performed before hospital discharge, 3 or 6 months after surgery and once each year after hospital discharge.
Surgical technique After anaesthesia induction, intra-arterial cannulation in the radial and femoral arteries were performed for invasive arterial blood pressure measurement. A right subclavicular incision was made and the right axillary artery (RAA) was exposed. Then, mobilization of the transverse arch and brachiocephalic arteries was performed. CPB was initiated after cannulation of the RAA and dual-stage atriocaval cannulation of the right atrium was performed via a median sternotomy incision. Cannulation of the RAA was used for CPB and SACP. The arterial line was bifurcated for the RAA and for antegrade perfusion through one limb of a four-branched prosthetic graft.
3
AORTIC SURGERY
J.-M. Zhu et al. / European Journal of Cardio-Thoracic Surgery
Figure 2: The stented elephant trunk procedure (A); stented elephant trunk procedure with LSCA–LCCA transposition (B); and stented elephant trunk procedure with LSCA–LCCA and ILVA–LCCA transposition (C). ILVA: isolated left vertebral artery; LCCA: left common carotid artery; LSCA: left subclavian artery.
Myocardial protection was maintained using intermittent antegrade perfusion of cold-blood cardioplegic solution. Aortic root procedures (if indicated) were performed during the cooling stage. As soon as the nasopharyngeal temperature reached 23–25°C, circulatory arrest was established and the brachiocephalic arteries were cross-clamped. In practice, blood pressure measurement of the left radial artery and/or back-bleeding through the left common carotid artery (LCCA) were performed to assess whether intraoperative left hemispheric cerebral circulation was adequate (left radial arterial pressure greater than or equal to 15–20 mmHg). Unilateral SACP was started through the RAA and the brain was perfused at 5–10 ml/kg/min. The stented elephant trunk (Cronus, Microport, Shanghai, China) technique for type B dissection has been described in detail in our previous reports [5]. It consisted of a Gianturco-type self-expandable metallic stent and a high-porosity woven Dacron graft in a bound, compressed state. The proximal and distal end of the surgical stent graft had 1 cm of extra vascular graft, which was used for sewing [5–7]. A half circumferential or a longitudinal incision was made on the distal end of the transverse arch. The extent of aortic dissection involvement, site of the intimal tear and the involved aortic branch vessel were inspected. We prefer a longitudinal incision because of better exposure and easier manipulation. In patients with inadequate proximal fixation zones, the ILVA was reconstructed according to the extent of type B dissection with retrograde extension into the aortic arch (whether the LSCA and ILVA were involved or not): (i) when the distal aortic arch was not involved by the dissection, only the stented elephant trunk procedure was performed (Fig. 2A). After the stented elephant trunk was implanted into the true lumen of the distal aorta, the surgical graft was firmly attached to the aortic wall using the suture line. (ii) If the LSCA origin was involved by the dissection, concomitant LSCA–LCCA transposition was performed (Fig. 2B). After the LSCA was transected circumferentially, 0.5–1.0 cm distal to its origin, the origin of the LSCA was sutured. Then, the LSCA was anastomosed to the LCCA in an end-to-side fashion. The false lumen distal to the ILVA origin was excluded completely using the surgical graft. (iii) If the ILVA origin was involved by the dissection,
the ILVA was anastomosed to the LCCA in the same manner (Fig. 2C).
RESULTS Surgical data CPB duration was 108–177 (mean 137 ± 26) min; aortic crossclamp time was 32–89 (mean 53 ± 19) min and SACP time was 18– 59 (mean 32 ± 14) min. Concomitant LSCA–LCCA transposition was performed in 4 patients, LSCA–ascending aorta bypass in 1 and ILVA–LCCA transposition in 3 (Table 1).
Morbidity and mortality There were no in-hospital deaths. The median ventilator support time was 16 ± 3 (range 11–20) h. The median ICU stay was 38 ± 5 (range 31–42) h. The estimated blood loss during operation was 1333 ± 673 ml and the average red cell transfusion during hospitalization was 5.4 ± 5.0 (range, 0–13) U. After implantation of the stented elephant trunk into the distal aorta, lower limb and visceral ischaemia was ameliorated. Postoperative continuous renal replacement therapy was not required in the 1 patient with preoperative renal dysfunction. No cerebral complications were observed in this group. All patients recovered and were discharged from the hospital.
Follow-up period All cases were followed up for a mean of 44 ± 19 (range 19–70) months; there were no late deaths. One patient underwent TEVAR due to a large tear in his descending aorta, distal to the stented elephant trunk. Spinal cord injury and visceral organ ischaemia were not observed during the follow-up period. Patients resumed their normal activities and antihypertensive therapy after hospital discharge. The anastomotic sites, between the LSCA and the LCCA, and between the ILVA and the LCCA, were patency, as confirming by postoperative CT (Fig. 3). Thrombosis in the false lumen around the
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J.-M. Zhu et al. / European Journal of Cardio-Thoracic Surgery
Figure 3: Postoperative computed tomography images of a patient using the stented elephant trunk procedure with LSCA–LCCA and ILVA–LCCA transposition (ILVA: isolated left vertebral artery; LCCA: left common carotid artery; LSCA: left subclavian artery). The anastomotic site between the LSCA and the LCCA was patent. After remodelling of the aortic wall, the true lumen in the descending aorta was resumed during follow-up (A).
surgical graft was observed in 100% of patients. Thrombus formation extending to the diaphragmatic level was found in 85.7% (6/7) of patients and at the diaphragmatic level in 42.9% (3/7) patients. The mean diameter of the descending aorta decreased from 38.4 ± 4.6 to 29.7 ± 3.7 mm during follow-up.
DISCUSSION In patients without suitable proximal landing zones, TEVAR of type B dissection with an ILVA remains a challenging problem. LSCA coverage results in an adequate proximal seal in some patients undergoing TEVAR; however, this can also result in endoleak and malperfusion of the upper extremity, brain and spinal cord in others [8]. In patients with an ILVA undergoing TEVAR, LSCA revascularization is indicated [9]. However, pre-emptive LSCA revascularization offers no protection against potential neurological complications [10]. During TEVAR, overall persistent complications of LSCA revascularization have been reported in 7.5–9.4% of patients [4, 11]. More importantly, partial or even complete debranching procedures were required when the distal aortic arch was involved in the type B dissection. High mortality and morbidity rates were associated with hybrid aortic arch repair for complicated type B dissection [12–14]. Additionally, managing stent-graft failure was an intractable problem because the need to remove a failed endograft increased the complexity of the aortic reconstruction. To attenuate mortality and morbidity of hybrid aortic arch repair, a stented elephant trunk technique was performed in our centre for complicated type B dissection with an ILVA, in patients without a suitable proximal landing zone for TEVAR. This technique was performed when the primary tear was adjacent to the
origin of the LSCA (n = 2). If the distal aorta was involved by the dissection, LSCA revascularization was performed (n = 5). Although bypass of the LSCA to the ascending aorta was completed in 1 case expeditiously, we prefer LSCA–LCCA transposition (n = 4) due to the long-term patency of autologous brachiocephalic vessels. If the ILVA origin was involved by the dissection, concomitant ILVA–LCCA transposition was performed (n = 3). Total arch replacement combined with the stented elephant trunk technique was performed if the LCCA was involved by the aortic dissection or the diameter of the aortic arch was greater than 50 mm, as our previous report described [3, 15, 16]. Moderate or greater regurgitation of the aortic valve is necessary for surgical treatment of complicated type B dissection with concomitant aortic regurgitation. As for an aneurysm of the aortic root or ascending aorta, surgical intervention was indicated when the diameter of the aortic root or ascending aorta was more than 50 or 45 mm with concomitant repair of the aortic valve. Due to extensiveness of the surgery itself, the stented elephant trunk procedure as applied to complicated type B dissection remains controversial. Patients tended to be younger in this group (mean age 53 ± 6 years) and would survive longer after successful surgery. As it consists of a woven Dacron graft, the stented elephant trunk ensures a desirable long-term result. Meanwhile, native LSCA and/or ILVA transposition also has the advantage of long-term patency. If late surgery is required, it becomes safer and easier to perform the anastomosis between the distal end of the stent graft and the Dacron prosthesis [17]; the stented elephant trunk can also be used as a proximal landing zone [18]. Thus, we thought the stented elephant trunk procedure would be justified for this select group of patients. The primary objective of surgical treatment of type B dissection with an ILVA is to preserve the ILVA, as is done in the management of type A dissection with an ILVA [3]. A high incidence of an incomplete circle of Willis has been reported in the Chinese population [7]. In certain aortic arch anomalies, the LCCA does not supply normal blood flow and the ILVA compensates for this [19]. Ligation of the ILVA was performed only when the ILVA was thin, after confirmation of sufficient collateral pathways and a complete circle of Willis. Satisfactory results were demonstrated in this study, without postoperative neurological deficits or in-hospital mortality. We also demonstrated that unilateral SACP was safer after evaluation for adequate left hemispheric cerebral circulation. However, this study was limited by the small number of participants and lack of a control group.
CONCLUSION In conclusion, satisfactory surgical results were obtained for complicated type B aortic dissection with an ILVA using the stented elephant trunk technique. This technique is an alternative to TEVAR for complicated type B dissection with an ILVA and inadequate proximal landing zones. As the follow-up period was relatively short, long-term follow-up is required to confirm the durability of this technique for complicated type B dissection with an ILVA.
Funding This study was supported by grants from The Capital Health Research and Development of Special (2011-2006-05). Conflict of interest: none declared.
REFERENCES [1] Naito Y, Nakajima M, Inoue H, Mizutani E, Tsuchiya K. Successful treatment of a mycotic aortic arch aneurysm associated with an isolated left vertebral artery. J Thorac Cardiovasc Surg 2003;126:883–5. [2] Yamashiro S, Kuniyoshi Y, Arakaki K, Inafuku H, Morishima Y, Kise Y. Total arch replacement with associated anomaly of the left vertebral artery. Ann Thorac Cardiovasc Surg 2010;16:216–9. [3] Qi R, Sun L, Zhu J, Liu Y, Zheng J, Li C et al. Total arch replacement in patients with aortic dissection with an isolated left vertebral artery. Ann Thorac Surg 2013;95:36–40. [4] Lee TC, Andersen ND, Williams JB, Bhattacharya SD, McCann RL, Hughes GC. Results with a selective revascularization strategy for left subclavian artery coverage during thoracic endovascular aortic repair. Ann Thorac Surg 2011;92:97–102; discussion 102–3. [5] Zhu JM, Cheng LJ, Liu YM, Zheng J, Qiao ZY, Li CN et al. One-stage repair for Stanford type B aortic dissection concomitant with cardiac diseases: open stented elephant trunk technique combined with cardiac operation. Thorac Cardiovasc Surg 2012;60:11–6. [6] Sun L, Qi R, Chang Q, Zhu J, Liu Y, Yu C et al. Surgery for Marfan patients with acute type a dissection using a stented elephant trunk procedure. Ann Thorac Surg 2008;86:1821–5. [7] Sun LZ, Qi RD, Chang Q, Zhu JM, Liu YM, Yu CT et al. Is total arch replacement combined with stented elephant trunk implantation justified for patients with chronic Stanford type A aortic dissection? J Thorac Cardiovasc Surg 2009;138:892–6. [8] Rizvi AZ, Murad MH, Fairman RM, Erwin PJ, Montori VM. The effect of left subclavian artery coverage on morbidity and mortality in patients undergoing endovascular thoracic aortic interventions: a systematic review and meta-analysis. J Vasc Surg 2009;50:1159–69. [9] Feezor RJ, Lee WA. Management of the left subclavian artery during TEVAR. Semin Vasc Surg 2009;22:159–64.
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[10] Cooper DG, Walsh SR, Sadat U, Noorani A, Hayes PD, Boyle JR. Neurological complications after left subclavian artery coverage during thoracic endovascular aortic repair: a systematic review and meta-analysis. J Vasc Surg 2009;49:1594–601. [11] Saouti N, Hindori V, Morshuis WJ, Heijmen RH. Left subclavian artery revascularization as part of thoracic stent grafting. Eur J Cardiothorac Surg 2015;47:120–5. [12] Cochennec F, Tresson P, Cross J, Desgranges P, Allaire E, Becquemin JP. Hybrid repair of aortic arch dissections. J Vasc Surg 2013;57:1560–7. [13] Bunger CM, Kische S, Liebold A, Leissner M, Glass A, Schareck W et al. Hybrid aortic arch repair for complicated type B aortic dissection. J Vasc Surg 2013;58:1490–6. [14] Geisbusch P, Kotelis D, Muller-Eschner M, Hyhlik-Durr A, Bockler D. Complications after aortic arch hybrid repair. J Vasc Surg 2011;53: 935–41. [15] Sun LZ, Zhao X, Chang Q, Zhu JM, Liu YM, Yu CT et al. Repair of chronic type B dissection with aortic arch involvement using a stented elephant trunk procedure. Ann Thorac Surg 2010;90:95–100. [16] Zhao HP, Zhu JM, Ma WG, Zheng J, Liu YM, Sun LZ. Total arch replacement with stented elephant trunk technique for acute type B aortic dissection involving the aortic arch. Ann Thorac Surg 2012;93: 1517–22. [17] Pichlmaier MA, Teebken OE, Khaladj N, Weidemann J, Galanski M, Haverich A. Distal aortic surgery following arch replacement with a frozen elephant trunk. Eur J Cardiothorac Surg 2008;34:600–4. [18] Uchida N, Kodama H, Katayama K, Takasaki T, Katayama A, Takahashi S et al. Endovascular aortic repair as second-stage surgery after hybrid open arch repair by the frozen elephant trunk technique for extended thoracic aneurysm. Ann Thorac Cardiovasc Surg 2013;19:257–61. [19] Ad N, Lee P, Cox JL. Type A aortic dissection with associated anomaly of the carotid and vertebral vessels. J Thorac Cardiovasc Surg 2002;123: 570–1.
AORTIC SURGERY
J.-M. Zhu et al. / European Journal of Cardio-Thoracic Surgery
ORIGINAL ARTICLE
European Journal of Cardio-Thoracic Surgery (2015) 1–5 doi:10.1093/ejcts/ezv242
Repair of complicated type B dissection with an isolated left vertebral artery using the stented elephant trunk technique Jun-Ming Zhu, Rui-Dong Qi, Yong-Min Liu, Jun Zheng, Xiao-Yan Xing and Li-Zhong Sun* Beijing Aortic Disease Center, Beijing Institute of Heart, Lung and Blood Vessel Diseases & Beijing Anzhen Hospital, Capital Medical University, Beijing, China * Corresponding author. Beijing Aortic Disease Center, Beijing Anzhen Hospital, Capital Medical University, 2 Anzhen Road, Beijing 100029, China. Tel: +86-10-64456168; fax: +86-10-64456168; e-mail: [email protected] (L.-Z. Sun). Received 17 March 2015; received in revised form 30 May 2015; accepted 15 June 2015
Abstract OBJECTIVES: The presence of an isolated left vertebral artery (ILVA) remains a challenging issue for thoracic endovascular aortic repair (TEVAR) of type B dissection if the proximal landing zones are inadequate. We retrospectively reviewed our experience of the surgical management of complicated type B dissection with an ILVA using the stented elephant trunk technique. METHODS: Between February 2009 and May 2013, 7 patients with complicated type B dissection (acute = 2 and chronic = 5) underwent the stented elephant trunk procedure under hypothermic cardiopulmonary bypass with selective antegrade cerebral perfusion. All the patients were males with a median age of 53 ± 6 (range 42–59) years. Preoperative lower limb ischaemia was observed in 1 patient, renal dysfunction in 1 patient and visceral ischaemia in 1 patient. RESULTS: There were no in-hospital deaths. The median ventilator support time was 16 ± 3 (range 11–20) h. Ischaemia of the lower limb and viscera was ameliorated after surgical stent-graft implantation. Continuous renal replacement therapy was not required in patients with preoperative renal dysfunction after surgery. No neurological deficits were observed in any patients prior to hospital discharge. One patient underwent TEVAR due to distal aortic dilatation within the mean follow-up period, which was 44 ± 19 months. CONCLUSION: Repair of complicated type B dissection with an ILVA using the stented elephant trunk technique was associated with satisfactory surgical results in patients with inadequate proximal fixation zones. This technique is an alternative to TEVAR for complicated type B dissection with inadequate proximal landing zones. Keywords: Type B dissection • Stented elephant trunk technique • Isolated left vertebral artery
INTRODUCTION
METHODS
An isolated left vertebral artery (ILVA), which arises directly from the aortic arch, is not uncommon among aortic arch vessel anomalies. The presence of an ILVA has considerable impact on the choice of aortic arch reconstruction techniques and cerebral protection methods in patients with aortic arch lesions. Improper management of the ILVA may result in ischaemia or infarction of the brain if the arterial circle of Willis is incomplete [1, 2]. In patients with type A dissection with an ILVA, total arch replacement using the separated graft technique was described in detail in our previous report [3]. In patients with an inadequate proximal landing zone, complicated type B dissection with an ILVA can be challenging for thoracic endovascular aortic repair (TEVAR). During TEVAR, coverage and revascularization of the left subclavian artery (LSCA) in patients with type B dissection with an ILVA have been reported [4]. In this study, we reviewed our experience with the surgical treatment of complicated type B dissection with an ILVA and inadequate proximal landing zones, using the stented elephant trunk technique.
Patients Between February 2009 and May 2013, 7 patients with complicated type B dissection and an ILVA (Fig. 1) underwent surgical treatment using a stented elephant trunk procedure under hypothermic cardiopulmonary bypass (CPB) with selective antegrade cerebral perfusion (SACP) at Beijing Aortic Disease Center, Beijing Anzhen Hospital. This technique was approved by the institutional review board of Capital Medical University. The mean age of our patient cohort was 53 ± 6 (range 42–59) years; all patients were male. The mean interval between the onset of aortic dissection and surgery was 42 ± 34 (range, 10–110) days. Two patients underwent surgery during the acute stage (within 2 weeks of symptom onset). Aortic dissection was confirmed prior to surgery by computed tomography (CT). Six patients had a history of hypertension; a failed prior TEVAR was present in 1 patient. In this group, type B dissection was complicated by uncontrolled
© The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
AORTIC SURGERY
Cite this article as: Zhu J-M, Qi R-D, Liu Y-M, Zheng J, Xing X-Y, Sun L-Z. Repair of complicated type B dissection with an isolated left vertebral artery using the stented elephant trunk technique. Eur J Cardiothorac Surg 2015; doi:10.1093/ejcts/ezv242.
J.-M. Zhu et al. / European Journal of Cardio-Thoracic Surgery
2
Figure 1: Preoperative computed tomography images of a patient with type B dissection with an ILVA. ILVA: isolated left vertebral artery; FL: false lumen; LSCA: left subclavian artery; TL: true lumen. The ILVA was involved by the dissection (A–C).
Table 1: Clinical profiles of patients with type B dissection with the ILVA No.
Age
Sex
Acuity
Symptoms and findings
Location of the primary tear
Distal arch involvement
Concomitant procedure
Complication
Follow-up
1
55
M
C
Uncontrolled HT
LSCA
AA–LSCA bypass
No
Alive
2
48
M
C
Uncontrolled HT
No
TEVAR
3
56
M
C
Lower limb ischaemia
4
59
M
C
5
59
M
A
Failure of TEVAR/persistent pain HT/persistent pain
6
53
M
A
HT/visceral ischaemia
7
42
M
C
Previous TEVAR/HT/DB/CAD/ renal dysfunction
Adjacent to the LSCAO Adjacent to the LSCAO Adjacent to the LSCAO Adjacent to the LSCAO Adjacent to the LSCAO Adjacent to the LSCAO Distal to the LSCAO
LSCA
LSCA–LCCA transposition
No
Alive
LSCA
LSCA–LCCA/ILVA–LSCA transposition LSCA–LCCA /ILVA–LSCA transposition LSCA–LCCA/ILVA–LCCA transposition
No
Alive
No
Alive
No
Alive
No
Alive
LSCA LSCAO
HT: hypertension; AA: ascending aorta; LSCA: left subclavian artery; LSCAO: left subclavian artery origin; LCCA: left common carotid artery; ILVA: isolated left vertebral artery; DB: diabetes mellitus; CAD: coronary artery disease; TEVAR: thoracic endovascular aortic repair.
hypertension in 2 patients, persistent pain in 2 patients, lower limb ischaemia in 1 patient, visceral ischaemia in 1 patient and renal dysfunction in 1 patient. Preoperative complications were common (Table 1). The primary tear was located near the origin of the LSCA in 6 patients and distal to the origin of the LSCA in the subject with the failed prior TEVAR. Involvement of the LSCA origin was present in 5 patients and involvement of the ILVA origin in 3. The dissection extended into the abdominal aorta in 3 cases and into the iliac artery in 4 cases. Postoperative CT and echocardiography were recommended to be performed before hospital discharge, 3 or 6 months after surgery and once each year after hospital discharge.
Surgical technique After anaesthesia induction, intra-arterial cannulation in the radial and femoral arteries were performed for invasive arterial blood pressure measurement. A right subclavicular incision was made and the right axillary artery (RAA) was exposed. Then, mobilization of the transverse arch and brachiocephalic arteries was performed. CPB was initiated after cannulation of the RAA and dual-stage atriocaval cannulation of the right atrium was performed via a median sternotomy incision. Cannulation of the RAA was used for CPB and SACP. The arterial line was bifurcated for the RAA and for antegrade perfusion through one limb of a four-branched prosthetic graft.
3
AORTIC SURGERY
J.-M. Zhu et al. / European Journal of Cardio-Thoracic Surgery
Figure 2: The stented elephant trunk procedure (A); stented elephant trunk procedure with LSCA–LCCA transposition (B); and stented elephant trunk procedure with LSCA–LCCA and ILVA–LCCA transposition (C). ILVA: isolated left vertebral artery; LCCA: left common carotid artery; LSCA: left subclavian artery.
Myocardial protection was maintained using intermittent antegrade perfusion of cold-blood cardioplegic solution. Aortic root procedures (if indicated) were performed during the cooling stage. As soon as the nasopharyngeal temperature reached 23–25°C, circulatory arrest was established and the brachiocephalic arteries were cross-clamped. In practice, blood pressure measurement of the left radial artery and/or back-bleeding through the left common carotid artery (LCCA) were performed to assess whether intraoperative left hemispheric cerebral circulation was adequate (left radial arterial pressure greater than or equal to 15–20 mmHg). Unilateral SACP was started through the RAA and the brain was perfused at 5–10 ml/kg/min. The stented elephant trunk (Cronus, Microport, Shanghai, China) technique for type B dissection has been described in detail in our previous reports [5]. It consisted of a Gianturco-type self-expandable metallic stent and a high-porosity woven Dacron graft in a bound, compressed state. The proximal and distal end of the surgical stent graft had 1 cm of extra vascular graft, which was used for sewing [5–7]. A half circumferential or a longitudinal incision was made on the distal end of the transverse arch. The extent of aortic dissection involvement, site of the intimal tear and the involved aortic branch vessel were inspected. We prefer a longitudinal incision because of better exposure and easier manipulation. In patients with inadequate proximal fixation zones, the ILVA was reconstructed according to the extent of type B dissection with retrograde extension into the aortic arch (whether the LSCA and ILVA were involved or not): (i) when the distal aortic arch was not involved by the dissection, only the stented elephant trunk procedure was performed (Fig. 2A). After the stented elephant trunk was implanted into the true lumen of the distal aorta, the surgical graft was firmly attached to the aortic wall using the suture line. (ii) If the LSCA origin was involved by the dissection, concomitant LSCA–LCCA transposition was performed (Fig. 2B). After the LSCA was transected circumferentially, 0.5–1.0 cm distal to its origin, the origin of the LSCA was sutured. Then, the LSCA was anastomosed to the LCCA in an end-to-side fashion. The false lumen distal to the ILVA origin was excluded completely using the surgical graft. (iii) If the ILVA origin was involved by the dissection,
the ILVA was anastomosed to the LCCA in the same manner (Fig. 2C).
RESULTS Surgical data CPB duration was 108–177 (mean 137 ± 26) min; aortic crossclamp time was 32–89 (mean 53 ± 19) min and SACP time was 18– 59 (mean 32 ± 14) min. Concomitant LSCA–LCCA transposition was performed in 4 patients, LSCA–ascending aorta bypass in 1 and ILVA–LCCA transposition in 3 (Table 1).
Morbidity and mortality There were no in-hospital deaths. The median ventilator support time was 16 ± 3 (range 11–20) h. The median ICU stay was 38 ± 5 (range 31–42) h. The estimated blood loss during operation was 1333 ± 673 ml and the average red cell transfusion during hospitalization was 5.4 ± 5.0 (range, 0–13) U. After implantation of the stented elephant trunk into the distal aorta, lower limb and visceral ischaemia was ameliorated. Postoperative continuous renal replacement therapy was not required in the 1 patient with preoperative renal dysfunction. No cerebral complications were observed in this group. All patients recovered and were discharged from the hospital.
Follow-up period All cases were followed up for a mean of 44 ± 19 (range 19–70) months; there were no late deaths. One patient underwent TEVAR due to a large tear in his descending aorta, distal to the stented elephant trunk. Spinal cord injury and visceral organ ischaemia were not observed during the follow-up period. Patients resumed their normal activities and antihypertensive therapy after hospital discharge. The anastomotic sites, between the LSCA and the LCCA, and between the ILVA and the LCCA, were patency, as confirming by postoperative CT (Fig. 3). Thrombosis in the false lumen around the
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J.-M. Zhu et al. / European Journal of Cardio-Thoracic Surgery
Figure 3: Postoperative computed tomography images of a patient using the stented elephant trunk procedure with LSCA–LCCA and ILVA–LCCA transposition (ILVA: isolated left vertebral artery; LCCA: left common carotid artery; LSCA: left subclavian artery). The anastomotic site between the LSCA and the LCCA was patent. After remodelling of the aortic wall, the true lumen in the descending aorta was resumed during follow-up (A).
surgical graft was observed in 100% of patients. Thrombus formation extending to the diaphragmatic level was found in 85.7% (6/7) of patients and at the diaphragmatic level in 42.9% (3/7) patients. The mean diameter of the descending aorta decreased from 38.4 ± 4.6 to 29.7 ± 3.7 mm during follow-up.
DISCUSSION In patients without suitable proximal landing zones, TEVAR of type B dissection with an ILVA remains a challenging problem. LSCA coverage results in an adequate proximal seal in some patients undergoing TEVAR; however, this can also result in endoleak and malperfusion of the upper extremity, brain and spinal cord in others [8]. In patients with an ILVA undergoing TEVAR, LSCA revascularization is indicated [9]. However, pre-emptive LSCA revascularization offers no protection against potential neurological complications [10]. During TEVAR, overall persistent complications of LSCA revascularization have been reported in 7.5–9.4% of patients [4, 11]. More importantly, partial or even complete debranching procedures were required when the distal aortic arch was involved in the type B dissection. High mortality and morbidity rates were associated with hybrid aortic arch repair for complicated type B dissection [12–14]. Additionally, managing stent-graft failure was an intractable problem because the need to remove a failed endograft increased the complexity of the aortic reconstruction. To attenuate mortality and morbidity of hybrid aortic arch repair, a stented elephant trunk technique was performed in our centre for complicated type B dissection with an ILVA, in patients without a suitable proximal landing zone for TEVAR. This technique was performed when the primary tear was adjacent to the
origin of the LSCA (n = 2). If the distal aorta was involved by the dissection, LSCA revascularization was performed (n = 5). Although bypass of the LSCA to the ascending aorta was completed in 1 case expeditiously, we prefer LSCA–LCCA transposition (n = 4) due to the long-term patency of autologous brachiocephalic vessels. If the ILVA origin was involved by the dissection, concomitant ILVA–LCCA transposition was performed (n = 3). Total arch replacement combined with the stented elephant trunk technique was performed if the LCCA was involved by the aortic dissection or the diameter of the aortic arch was greater than 50 mm, as our previous report described [3, 15, 16]. Moderate or greater regurgitation of the aortic valve is necessary for surgical treatment of complicated type B dissection with concomitant aortic regurgitation. As for an aneurysm of the aortic root or ascending aorta, surgical intervention was indicated when the diameter of the aortic root or ascending aorta was more than 50 or 45 mm with concomitant repair of the aortic valve. Due to extensiveness of the surgery itself, the stented elephant trunk procedure as applied to complicated type B dissection remains controversial. Patients tended to be younger in this group (mean age 53 ± 6 years) and would survive longer after successful surgery. As it consists of a woven Dacron graft, the stented elephant trunk ensures a desirable long-term result. Meanwhile, native LSCA and/or ILVA transposition also has the advantage of long-term patency. If late surgery is required, it becomes safer and easier to perform the anastomosis between the distal end of the stent graft and the Dacron prosthesis [17]; the stented elephant trunk can also be used as a proximal landing zone [18]. Thus, we thought the stented elephant trunk procedure would be justified for this select group of patients. The primary objective of surgical treatment of type B dissection with an ILVA is to preserve the ILVA, as is done in the management of type A dissection with an ILVA [3]. A high incidence of an incomplete circle of Willis has been reported in the Chinese population [7]. In certain aortic arch anomalies, the LCCA does not supply normal blood flow and the ILVA compensates for this [19]. Ligation of the ILVA was performed only when the ILVA was thin, after confirmation of sufficient collateral pathways and a complete circle of Willis. Satisfactory results were demonstrated in this study, without postoperative neurological deficits or in-hospital mortality. We also demonstrated that unilateral SACP was safer after evaluation for adequate left hemispheric cerebral circulation. However, this study was limited by the small number of participants and lack of a control group.
CONCLUSION In conclusion, satisfactory surgical results were obtained for complicated type B aortic dissection with an ILVA using the stented elephant trunk technique. This technique is an alternative to TEVAR for complicated type B dissection with an ILVA and inadequate proximal landing zones. As the follow-up period was relatively short, long-term follow-up is required to confirm the durability of this technique for complicated type B dissection with an ILVA.
Funding This study was supported by grants from The Capital Health Research and Development of Special (2011-2006-05). Conflict of interest: none declared.
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