European Journal of Cardio-Thoracic Surgery Advance Access published February 4, 2016
ORIGINAL ARTICLE
European Journal of Cardio-Thoracic Surgery (2016) 1–7 doi:10.1093/ejcts/ezw020
Thoracic endovascular aortic repair for degenerative distal arch aneurysm can be used as a standard procedure in high-risk patients† Takayuki Shijoa, Toru Kuratanib, Kei Torikaia, Kazuo Shimamuraa, Tomohiko Sakamotoa, Tomoaki Kudob, Kenta Masadaa, Mitsuyoshi Takaharac and Yoshiki Sawaa,* a b c
Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine, Osaka, Japan Department of Minimally Invasive Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan Department of Diabetes Care Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
* Corresponding author. 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan. Tel: +81-6-6879 3154; fax: +81-6-6879 3163; e-mail: [email protected] (Y. Sawa). Received 5 September 2015; received in revised form 22 December 2015; accepted 11 January 2016
Abstract OBJECTIVES: In recent years, supra-aortic rerouting and thoracic endovascular aortic repair (TEVAR) for treating aortic arch pathology have emerged as a less invasive option for high-risk patients. This study aimed to assess our strategy for preventing stroke and improving late outcomes after supra-aortic rerouting and TEVAR. METHODS: Between July 2008 and July 2015, we performed 280 cases of TEVAR for arch pathologies, using manufactured stent grafts. This study reviewed 101 patients who underwent supra-aortic rerouting and TEVAR for degenerative distal arch aneurysms (80 men, mean age 73.1 years, Zone 1/Zone 2 = 48/53). Since 2011, we have routinely used the brain protection method, which comprises blocking native forward flow from the left common carotid artery (LCA) and left subclavian artery (LSA) for zone 1 cases and the LSA for zone 2 cases before TEVAR. RESULTS: The mean operation time was 178 ± 65 min. The stroke and 30-day death rates were 3 and 1%, respectively. Before the brain protection method was introduced, the perioperative risk factor for stroke was atheroma Grade ≥III (P = 0.035). Proximal landing zone (P = 0.58) and LSA sacrifice (P = 1.00) were not risk factors for stroke. No strokes occurred after using the brain protection method (before protection: 6% and after protection: 0%). Regarding late results, the rate of freedom from aorta-related death at 1 and 4 years was 97 and 95%, respectively. The rate of freedom from aortic events at 1 and 4 years was 91 and 86%, respectively. During follow-up, no type Ia endoleak developed and one type A dissection was observed. CONCLUSIONS: Our strategy for supra-aortic rerouting and TEVAR showed satisfactory early and late results. The chief risk factor for perioperative stroke was atheroma, and blocking native forward flow from the LCA and the LSA prior to the TEVAR procedure helped prevent stroke. Keywords: Supra-aortic rerouting • Thoracic endovascular aortic repair • Stroke
INTRODUCTION Despite recent developments in surgical techniques and perioperative management, conventional distal arch repair for aortic aneurysms remains an invasive procedure, especially in high-risk patients [1–3]. As endoprosthesis technology has developed, hybrid repair for distal arch aneurysm has emerged as a less invasive alternative. The procedure is a combination of supra-aortic rerouting technique and thoracic endovascular aortic repair (debranching TEVAR) [4–6]. Although sternotomy and cardiopulmonary bypass are not required in debranching TEVAR for distal arch aneurysms, the chief problems are stroke and late aortic events. Regarding the TEVAR procedure, stroke is significantly related to mortality and morbidity [7]. Since 2011, we have introduced the brain protection method, which † Presented at the 29th Annual Meeting of the European Association for Cardiothoracic Surgery, Amsterdam, The Netherlands, 3–7 October 2015.
comprises blocking the native forward flow from the left common carotid artery (LCA) and left subclavian artery (LSA) before the endovascular aortic procedure. The aim of this study was to assess our strategy for preventing stroke and late outcomes.
MATERIALS AND METHODS Patient profiles Between July 2008 and July 2015, we performed 280 hybrid arch repairs by using a combination of supra-aortic debranching bypass and TEVAR. During this period, we performed this combined repair for all patients with arch pathology, excluding those with infected aneurysms. The pathology consisted of degenerative aneurysm in 183 patients, aortic dissection in 83, aortic trauma in 10 and other conditions in 4 patients (LSA aneurysm in 2 and coarctation in 2).
© The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
AORTIC SURGERY
Cite this article as: Shijo T, Kuratani T, Torikai K, Shimamura K, Sakamoto T, Kudo T et al. Thoracic endovascular aortic repair for degenerative distal arch aneurysm can be used as a standard procedure in high-risk patients. Eur J Cardiothorac Surg 2016; doi:10.1093/ejcts/ezw020.
T. Shijo et al. / European Journal of Cardio-Thoracic Surgery
2
Of the above patient population, this study included 101 cases (80 men, mean age 73.1 ± 9.1 years) of degenerative distal arch aneurysms (Zone 1: n = 48 and Zone 2: n = 53), excluding 82 cases of Zone 0. Aortic arch zones were categorized according to the classification by Ishimaru [8]. This retrospective record review was approved by the institutional review board of our hospital. Informed consent was obtained from each patient. The preoperative comorbidities and other patient characteristics are listed in Table 1.
Treatment strategy We decided on a treatment strategy for the proximal neck as follows: longer than 15–20 mm in length and 18–42 mm in diameter with cylindrical shape. We selected a proximal landing zone that would avoid severe atheroma at the stent graft tip. When an appropriate proximal landing zone was isolated in the arch area, we performed TEVAR with partial arch debranching (Zone 1 or 2).
When the arch area was not suitable as a proximal landing zone, we performed total arch rerouting and TEVAR into the ascending aorta (Zone 0) as previously reported [9]. Zone 0 cases need median sternotomy and ascending aortic manipulation, which potentially increases the risk of postoperative complications, including stroke. Therefore, we excluded the zone 0 cases in this study. We measured the anatomical detail of the entire aorta and peripheral arteries by using multidetector computed tomography (MDCT). The diameter, length and atheromatous changes at the proximal neck were carefully assessed. The stent graft diameter was selected as 10–20% oversizing of the native aortic diameter. As illustrated in Table 2, the mean diameter and length of the proximal neck were 32.7 ± 4.0 and 19.4 ± 5.9 mm, respectively. Various commercially available stent graft systems were used: TAG and CTAG (W. L. Gore and Associates, Flagstaff, AZ, USA), TX2 (Cook, Bloomington, IN, USA), Relay Plus and Relay NBS Plus (Bolton Medical, Sunrise, FL, USA) and Talent and Valiant (Medtronic, Inc., Santa Rosa, CA, USA).
Table 1: Patient characteristics
n Age (years) Sex (male) Cerebrovascular disease Coronary artery disease Chronic obstructive pulmonary disease Chronic heart failure Chronic kidney disease Previous cardiovascular surgery Diabetes mellitus Hypertension Dyslipidaemia Logistic EuroSCORE (%)
Total
Protection (−)
Protection (+)
P-value
101 73.1 ± 9.1 80 (79%) 19 (19%) 26 (26%) 22 (22%) 10 (10%) 9 (9%) 4 (4%) 20 (20%) 64 (63%) 18 (18%) 14.7 ± 10.5
53 73.3 ± 10.3 42 (79%) 11 (21%) 13 (25%) 15 (28%) 6 (11%) 5 (9%) 1 (2%) 9 (17%) 30 (57%) 11 (21%) 13.3 ± 9.2
48 72.9 ± 7.8 38 (79%) 8 (17%) 13 (27%) 7 (15%) 4 (8%) 4 (8%) 3 (6%) 11 (23%) 34 (71%) 7 (15%) 16.2 ± 11.7
– 0.54 1.00 0.62 0.82 0.15 0.74 1.00 0.34 0.47 0.15 0.45 0.22
Protection (−): patients without the brain protection method. Protection (+): patients with the brain protection method.
Table 2: Anatomical and procedural details
Maximum aneurysm diameter (mm) Proximal neck Diameter (mm) Length (mm) Atheroma grade I II III IV Proximal landing zone Zone 1 Zone 2 LSA sacrifice Proximal stent graft diameter (mm)
Total
Protection (−)
Protection (+)
P-value
57.4 ± 11.4
56.9 ± 11.0
58.0 ± 11.8
0.52
32.7 ± 4.0 19.4 ± 5.9
32.8 ± 4.7 20.0 ± 6.2
32.7 ± 3.1 18.7 ± 5.4
0.98 0.31
12 (12%) 48 (48%) 25 (25%) 16 (16%)
7 (13%) 28 (53%) 11 (21%) 7 (13%)
5 (10%) 20 (42%) 14 (29%) 9 (19%)
0.59
48 (48%) 53 (52%) 13 (13%) 36.6 ± 3.6
24 (45%) 29 (55%) 7 (13%) 36.7 ± 4.2
24 (50%) 24 (50%) 6 (13%) 36.5 ± 3.0
0.69
Protection (−): patients without the brain protection method. Protection (+): patients with the brain protection method. LSA: left subclavian artery.
1.00 0.91
Evaluation of the atheroma in the proximal landing zone Preoperative and postoperative contrast-enhanced MDCT was performed and all images were analysed on Aquarius workstation software (TeraRecon, Inc., San Mateo, CA, USA). The severity of the atheromatous change at the proximal landing zone was graded from I to IV by using the scale described by Gutsche et al. [10]. Grade I was normal (n = 12, 12%) with a smooth and continuous intimal surface. Grade II was intimal thickening from 3 to 5 mm (n = 48, 48%). Grade III was atheroma protruding within 5 mm into the aortic lumen (n = 25, 20%). Grade IV was atheroma that protruded more than 5 mm into the lumen and was pedunculated (n = 16, 16%).
Operative procedure With regard to rerouting of the supra-aortic vessels, an extraanatomical bypass from the right axillary artery to the left axillary artery and the LCA was performed for zone 1 cases by using a T-shaped ringed expanded polytetrafluoroethylene (ePTFE) graft. For zone 2 cases, a bypass from the right axillary artery or LCA to the left axillary artery was performed by using an ePTFE tube graft. When preoperative magnetic resonance angiography showed normal intracranial communication (the circle of Willis) and that
3
the risk of spinal cord ischaemia ( previous downstream aortic repair or extended aortic aneurysm) was low, we did not bypass the LSA. We sacrificed the LSA in 13 patients without revascularization (13%). Then, TEVAR was performed on the same day as the supra-aortic rerouting procedure in a hybrid surgical suite using fixed fluoroscopic equipment.
Brain protection method The brain protection method comprises blocking the native forward flow from the LCA and LSA for zone 1 cases, and only the LSA for zone 2 cases before TEVAR (Fig. 1). The method was introduced in 2011. In our patients, the baseline comorbidities were similar between patients with or without brain protection, as illustrated in Tables 1 and 2. In zone 1 cases, after performing supra-aortic rerouting as described above, the LCA was closed with the Hem-o-lok system (Weck Closure System, Research Triangle Park, NC, USA) at the proximal site of the bypass anastomosis and the LSA was occluded with a balloon catheter (Selecon MP catheter II, Terumo Clinical Supply, Gifu, Japan) at the proximal portion of the left vertebral artery (VA) during the TEVAR procedure. In zone 2 cases, the LSA was occluded in the same fashion after bypassing. After the stent graft was deployed, the LSA was embolized with a coil and the balloon was then deflated.
Figure 1: Brain protection method. Zone 1 case: after performing supra-aortic rerouting, the LCA was clipped at the proximal site of the bypass anastomosis and the LSA was occluded with a balloon catheter at the proximal portion of the left VA during the TEVAR procedure. Zone 2 case: LSA was occluded in the same fashion as in zone 1 cases. After the stent graft was deployed, the LSA was embolized with a coil and the balloon was deflated. LCA: left common carotid artery; LSA: left subclavian artery; VA: vertebral artery; TEVAR; thoracic endovascular aortic repair.
AORTIC SURGERY
T. Shijo et al. / European Journal of Cardio-Thoracic Surgery
T. Shijo et al. / European Journal of Cardio-Thoracic Surgery
4
Follow-up All patients were followed up in the outpatient department of our institution. MDCT was performed at the time of hospital discharge, 6 months postoperatively and yearly thereafter. Follow-up clinical status was obtained through medical records from the outpatient clinic.
Definitions of the endpoints and statistical analysis All statistical analyses were retrospectively performed by using JMP Pro 10.0.0 (SAS Institute, Inc., Cary, NC, USA). Continuous variables were presented as mean ± standard deviation. Categorical variables were presented as counts and percentages. Intergroup comparisons were performed by using Fisher’s exact test for categorical variables and the Mann–Whitney U-test for continuous variables. Outcome definitions were based on recommended reporting standards for endovascular aortic aneurysm repair [11]. Stroke was defined as any new focal or global neurological deficit lasting >24 h with radiographic abnormalities. Postoperative neurological deficit was evaluated by stroke neurologists. In this study, we compared the patients with or without the protection method. Additionally, factors potentially associated with stroke before the brain protection method was introduced were assessed by univariate analysis. Kaplan–Meier estimates were used to evaluate late outcomes. Aortic events and aorta-related death included aortic rupture or dissection, prosthetic infection, sac enlargement of more than 5 mm in diameter, endoleak and other procedure-related events.
RESULTS Early results Procedural success was achieved in all patients. The early clinical results are listed in Table 3. The mean operative time was 178 ± 65 min. Ninety patients (89%) were extubated in the operation room. The rates of death within 30 days after the operation (30-day death) and in-hospital death were 1% (n = 1) and 2% (n = 2), respectively. Other postoperative complications included acute coronary syndrome (n = 2, 2%) and prolonged mechanical
ventilation needed for longer than 72 h (n = 2, 2%). Eventually, 91 patients were discharged home (90%). There were no significant differences between the groups with or without the brain protection method, including stroke prevalence. Before the brain protection method was introduced, we observed 3 strokes, which were caused by multiple infarctions in the posterior cerebral circulation (Zone 2, n = 1), massive infarctions in the left hemisphere (Zone 1, n = 1) and multiple infarctions in the left cerebellum and left hemisphere (Zone 1, n = 1). All strokes were classified as having embolic aetiology after brain imaging was performed. The zone 2 patient did not awake from the postoperative coma and needed tracheostomy. One zone 1 patient with massive stroke died of multiple organ failure, probably caused by multiple embolization, on the sixth postoperative day. Another zone 1 patient almost recovered from the hemiparesis before discharge. After the brain protection method was introduced, 2 patients experienced postoperative spinal cord injury (Zone 1, n = 1 and Zone 2, n = 1). In the zone 1 case, preoperative CT showed severe atheroma (Grade IV) from the proximal neck of the arch to the distal descending aorta. Extensive coverage of the downstream aorta was required to exclude the aneurysm. The zone 2 patient had previously undergone abdominal aortic replacement. Although the procedure was performed uneventfully, her postoperative haemodynamics were unstable due to postoperative retroperitoneal haemorrhage, which was the access site for TEVAR. She then developed delayed paraparesis. Early endoleaks were assessed by performing intraoperative aortography and/or MDCT before discharge. Type Ia endoleak and type Ib endoleak were 2% (n = 2) and 2% (n = 2), respectively. Type III endoleak did not occur. One patient with type Ia endoleak was successfully treated with open surgical repair. Another type Ia endoleak case was followed without additional intervention due to his severe comorbidities, and he died of aneurysm rupture 2 months after the surgery. Two type Ib endoleak cases were successfully treated with additional TEVAR.
Assessment of the risk factors for stroke Table 4 summarizes the covariates and stroke prevalence with 95% confidence intervals before the brain protection method was
Table 3: Early outcomes
Operation time (min) Thirty-day death In-hospital death Stroke Spinal cord injury Prolonged mechanical ventilation Acute coronary syndrome Extubation in the operation room Home discharge Endoleak Ia Ib II III
Total
Protection (−)
Protection (+)
P-value
178 ± 65 1 (1%) 2 (2%) 3 (3%) 2 (2%) 2 (2%) 2 (2%) 90 (89%) 91 (90%)
181 ± 69 1 (2%) 2 (4%) 3 (6%) 0 2 (4%) 2 (4%) 46 (87%) 47 (89%)
175 ± 63 0 0 0 2 (4%) 0 0 44 (92%) 44 (92%)
0.63 1.00 0.50 0.24 0.22 0.50 0.50 0.53 0.74
2 (2%) 2 (2%) 9 (9%) 0
1 (2%) 2 (4%) 7 (13%) 0
1 (2%) 0 2 (4%) 0
1.00 0.50 0.16 –
Protection (−): patients without the brain protection method. Protection (+): patients with the brain protection method.
T. Shijo et al. / European Journal of Cardio-Thoracic Surgery
5
Age
ORIGINAL ARTICLE
European Journal of Cardio-Thoracic Surgery (2016) 1–7 doi:10.1093/ejcts/ezw020
Thoracic endovascular aortic repair for degenerative distal arch aneurysm can be used as a standard procedure in high-risk patients† Takayuki Shijoa, Toru Kuratanib, Kei Torikaia, Kazuo Shimamuraa, Tomohiko Sakamotoa, Tomoaki Kudob, Kenta Masadaa, Mitsuyoshi Takaharac and Yoshiki Sawaa,* a b c
Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine, Osaka, Japan Department of Minimally Invasive Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan Department of Diabetes Care Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
* Corresponding author. 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan. Tel: +81-6-6879 3154; fax: +81-6-6879 3163; e-mail: [email protected] (Y. Sawa). Received 5 September 2015; received in revised form 22 December 2015; accepted 11 January 2016
Abstract OBJECTIVES: In recent years, supra-aortic rerouting and thoracic endovascular aortic repair (TEVAR) for treating aortic arch pathology have emerged as a less invasive option for high-risk patients. This study aimed to assess our strategy for preventing stroke and improving late outcomes after supra-aortic rerouting and TEVAR. METHODS: Between July 2008 and July 2015, we performed 280 cases of TEVAR for arch pathologies, using manufactured stent grafts. This study reviewed 101 patients who underwent supra-aortic rerouting and TEVAR for degenerative distal arch aneurysms (80 men, mean age 73.1 years, Zone 1/Zone 2 = 48/53). Since 2011, we have routinely used the brain protection method, which comprises blocking native forward flow from the left common carotid artery (LCA) and left subclavian artery (LSA) for zone 1 cases and the LSA for zone 2 cases before TEVAR. RESULTS: The mean operation time was 178 ± 65 min. The stroke and 30-day death rates were 3 and 1%, respectively. Before the brain protection method was introduced, the perioperative risk factor for stroke was atheroma Grade ≥III (P = 0.035). Proximal landing zone (P = 0.58) and LSA sacrifice (P = 1.00) were not risk factors for stroke. No strokes occurred after using the brain protection method (before protection: 6% and after protection: 0%). Regarding late results, the rate of freedom from aorta-related death at 1 and 4 years was 97 and 95%, respectively. The rate of freedom from aortic events at 1 and 4 years was 91 and 86%, respectively. During follow-up, no type Ia endoleak developed and one type A dissection was observed. CONCLUSIONS: Our strategy for supra-aortic rerouting and TEVAR showed satisfactory early and late results. The chief risk factor for perioperative stroke was atheroma, and blocking native forward flow from the LCA and the LSA prior to the TEVAR procedure helped prevent stroke. Keywords: Supra-aortic rerouting • Thoracic endovascular aortic repair • Stroke
INTRODUCTION Despite recent developments in surgical techniques and perioperative management, conventional distal arch repair for aortic aneurysms remains an invasive procedure, especially in high-risk patients [1–3]. As endoprosthesis technology has developed, hybrid repair for distal arch aneurysm has emerged as a less invasive alternative. The procedure is a combination of supra-aortic rerouting technique and thoracic endovascular aortic repair (debranching TEVAR) [4–6]. Although sternotomy and cardiopulmonary bypass are not required in debranching TEVAR for distal arch aneurysms, the chief problems are stroke and late aortic events. Regarding the TEVAR procedure, stroke is significantly related to mortality and morbidity [7]. Since 2011, we have introduced the brain protection method, which † Presented at the 29th Annual Meeting of the European Association for Cardiothoracic Surgery, Amsterdam, The Netherlands, 3–7 October 2015.
comprises blocking the native forward flow from the left common carotid artery (LCA) and left subclavian artery (LSA) before the endovascular aortic procedure. The aim of this study was to assess our strategy for preventing stroke and late outcomes.
MATERIALS AND METHODS Patient profiles Between July 2008 and July 2015, we performed 280 hybrid arch repairs by using a combination of supra-aortic debranching bypass and TEVAR. During this period, we performed this combined repair for all patients with arch pathology, excluding those with infected aneurysms. The pathology consisted of degenerative aneurysm in 183 patients, aortic dissection in 83, aortic trauma in 10 and other conditions in 4 patients (LSA aneurysm in 2 and coarctation in 2).
© The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
AORTIC SURGERY
Cite this article as: Shijo T, Kuratani T, Torikai K, Shimamura K, Sakamoto T, Kudo T et al. Thoracic endovascular aortic repair for degenerative distal arch aneurysm can be used as a standard procedure in high-risk patients. Eur J Cardiothorac Surg 2016; doi:10.1093/ejcts/ezw020.
T. Shijo et al. / European Journal of Cardio-Thoracic Surgery
2
Of the above patient population, this study included 101 cases (80 men, mean age 73.1 ± 9.1 years) of degenerative distal arch aneurysms (Zone 1: n = 48 and Zone 2: n = 53), excluding 82 cases of Zone 0. Aortic arch zones were categorized according to the classification by Ishimaru [8]. This retrospective record review was approved by the institutional review board of our hospital. Informed consent was obtained from each patient. The preoperative comorbidities and other patient characteristics are listed in Table 1.
Treatment strategy We decided on a treatment strategy for the proximal neck as follows: longer than 15–20 mm in length and 18–42 mm in diameter with cylindrical shape. We selected a proximal landing zone that would avoid severe atheroma at the stent graft tip. When an appropriate proximal landing zone was isolated in the arch area, we performed TEVAR with partial arch debranching (Zone 1 or 2).
When the arch area was not suitable as a proximal landing zone, we performed total arch rerouting and TEVAR into the ascending aorta (Zone 0) as previously reported [9]. Zone 0 cases need median sternotomy and ascending aortic manipulation, which potentially increases the risk of postoperative complications, including stroke. Therefore, we excluded the zone 0 cases in this study. We measured the anatomical detail of the entire aorta and peripheral arteries by using multidetector computed tomography (MDCT). The diameter, length and atheromatous changes at the proximal neck were carefully assessed. The stent graft diameter was selected as 10–20% oversizing of the native aortic diameter. As illustrated in Table 2, the mean diameter and length of the proximal neck were 32.7 ± 4.0 and 19.4 ± 5.9 mm, respectively. Various commercially available stent graft systems were used: TAG and CTAG (W. L. Gore and Associates, Flagstaff, AZ, USA), TX2 (Cook, Bloomington, IN, USA), Relay Plus and Relay NBS Plus (Bolton Medical, Sunrise, FL, USA) and Talent and Valiant (Medtronic, Inc., Santa Rosa, CA, USA).
Table 1: Patient characteristics
n Age (years) Sex (male) Cerebrovascular disease Coronary artery disease Chronic obstructive pulmonary disease Chronic heart failure Chronic kidney disease Previous cardiovascular surgery Diabetes mellitus Hypertension Dyslipidaemia Logistic EuroSCORE (%)
Total
Protection (−)
Protection (+)
P-value
101 73.1 ± 9.1 80 (79%) 19 (19%) 26 (26%) 22 (22%) 10 (10%) 9 (9%) 4 (4%) 20 (20%) 64 (63%) 18 (18%) 14.7 ± 10.5
53 73.3 ± 10.3 42 (79%) 11 (21%) 13 (25%) 15 (28%) 6 (11%) 5 (9%) 1 (2%) 9 (17%) 30 (57%) 11 (21%) 13.3 ± 9.2
48 72.9 ± 7.8 38 (79%) 8 (17%) 13 (27%) 7 (15%) 4 (8%) 4 (8%) 3 (6%) 11 (23%) 34 (71%) 7 (15%) 16.2 ± 11.7
– 0.54 1.00 0.62 0.82 0.15 0.74 1.00 0.34 0.47 0.15 0.45 0.22
Protection (−): patients without the brain protection method. Protection (+): patients with the brain protection method.
Table 2: Anatomical and procedural details
Maximum aneurysm diameter (mm) Proximal neck Diameter (mm) Length (mm) Atheroma grade I II III IV Proximal landing zone Zone 1 Zone 2 LSA sacrifice Proximal stent graft diameter (mm)
Total
Protection (−)
Protection (+)
P-value
57.4 ± 11.4
56.9 ± 11.0
58.0 ± 11.8
0.52
32.7 ± 4.0 19.4 ± 5.9
32.8 ± 4.7 20.0 ± 6.2
32.7 ± 3.1 18.7 ± 5.4
0.98 0.31
12 (12%) 48 (48%) 25 (25%) 16 (16%)
7 (13%) 28 (53%) 11 (21%) 7 (13%)
5 (10%) 20 (42%) 14 (29%) 9 (19%)
0.59
48 (48%) 53 (52%) 13 (13%) 36.6 ± 3.6
24 (45%) 29 (55%) 7 (13%) 36.7 ± 4.2
24 (50%) 24 (50%) 6 (13%) 36.5 ± 3.0
0.69
Protection (−): patients without the brain protection method. Protection (+): patients with the brain protection method. LSA: left subclavian artery.
1.00 0.91
Evaluation of the atheroma in the proximal landing zone Preoperative and postoperative contrast-enhanced MDCT was performed and all images were analysed on Aquarius workstation software (TeraRecon, Inc., San Mateo, CA, USA). The severity of the atheromatous change at the proximal landing zone was graded from I to IV by using the scale described by Gutsche et al. [10]. Grade I was normal (n = 12, 12%) with a smooth and continuous intimal surface. Grade II was intimal thickening from 3 to 5 mm (n = 48, 48%). Grade III was atheroma protruding within 5 mm into the aortic lumen (n = 25, 20%). Grade IV was atheroma that protruded more than 5 mm into the lumen and was pedunculated (n = 16, 16%).
Operative procedure With regard to rerouting of the supra-aortic vessels, an extraanatomical bypass from the right axillary artery to the left axillary artery and the LCA was performed for zone 1 cases by using a T-shaped ringed expanded polytetrafluoroethylene (ePTFE) graft. For zone 2 cases, a bypass from the right axillary artery or LCA to the left axillary artery was performed by using an ePTFE tube graft. When preoperative magnetic resonance angiography showed normal intracranial communication (the circle of Willis) and that
3
the risk of spinal cord ischaemia ( previous downstream aortic repair or extended aortic aneurysm) was low, we did not bypass the LSA. We sacrificed the LSA in 13 patients without revascularization (13%). Then, TEVAR was performed on the same day as the supra-aortic rerouting procedure in a hybrid surgical suite using fixed fluoroscopic equipment.
Brain protection method The brain protection method comprises blocking the native forward flow from the LCA and LSA for zone 1 cases, and only the LSA for zone 2 cases before TEVAR (Fig. 1). The method was introduced in 2011. In our patients, the baseline comorbidities were similar between patients with or without brain protection, as illustrated in Tables 1 and 2. In zone 1 cases, after performing supra-aortic rerouting as described above, the LCA was closed with the Hem-o-lok system (Weck Closure System, Research Triangle Park, NC, USA) at the proximal site of the bypass anastomosis and the LSA was occluded with a balloon catheter (Selecon MP catheter II, Terumo Clinical Supply, Gifu, Japan) at the proximal portion of the left vertebral artery (VA) during the TEVAR procedure. In zone 2 cases, the LSA was occluded in the same fashion after bypassing. After the stent graft was deployed, the LSA was embolized with a coil and the balloon was then deflated.
Figure 1: Brain protection method. Zone 1 case: after performing supra-aortic rerouting, the LCA was clipped at the proximal site of the bypass anastomosis and the LSA was occluded with a balloon catheter at the proximal portion of the left VA during the TEVAR procedure. Zone 2 case: LSA was occluded in the same fashion as in zone 1 cases. After the stent graft was deployed, the LSA was embolized with a coil and the balloon was deflated. LCA: left common carotid artery; LSA: left subclavian artery; VA: vertebral artery; TEVAR; thoracic endovascular aortic repair.
AORTIC SURGERY
T. Shijo et al. / European Journal of Cardio-Thoracic Surgery
T. Shijo et al. / European Journal of Cardio-Thoracic Surgery
4
Follow-up All patients were followed up in the outpatient department of our institution. MDCT was performed at the time of hospital discharge, 6 months postoperatively and yearly thereafter. Follow-up clinical status was obtained through medical records from the outpatient clinic.
Definitions of the endpoints and statistical analysis All statistical analyses were retrospectively performed by using JMP Pro 10.0.0 (SAS Institute, Inc., Cary, NC, USA). Continuous variables were presented as mean ± standard deviation. Categorical variables were presented as counts and percentages. Intergroup comparisons were performed by using Fisher’s exact test for categorical variables and the Mann–Whitney U-test for continuous variables. Outcome definitions were based on recommended reporting standards for endovascular aortic aneurysm repair [11]. Stroke was defined as any new focal or global neurological deficit lasting >24 h with radiographic abnormalities. Postoperative neurological deficit was evaluated by stroke neurologists. In this study, we compared the patients with or without the protection method. Additionally, factors potentially associated with stroke before the brain protection method was introduced were assessed by univariate analysis. Kaplan–Meier estimates were used to evaluate late outcomes. Aortic events and aorta-related death included aortic rupture or dissection, prosthetic infection, sac enlargement of more than 5 mm in diameter, endoleak and other procedure-related events.
RESULTS Early results Procedural success was achieved in all patients. The early clinical results are listed in Table 3. The mean operative time was 178 ± 65 min. Ninety patients (89%) were extubated in the operation room. The rates of death within 30 days after the operation (30-day death) and in-hospital death were 1% (n = 1) and 2% (n = 2), respectively. Other postoperative complications included acute coronary syndrome (n = 2, 2%) and prolonged mechanical
ventilation needed for longer than 72 h (n = 2, 2%). Eventually, 91 patients were discharged home (90%). There were no significant differences between the groups with or without the brain protection method, including stroke prevalence. Before the brain protection method was introduced, we observed 3 strokes, which were caused by multiple infarctions in the posterior cerebral circulation (Zone 2, n = 1), massive infarctions in the left hemisphere (Zone 1, n = 1) and multiple infarctions in the left cerebellum and left hemisphere (Zone 1, n = 1). All strokes were classified as having embolic aetiology after brain imaging was performed. The zone 2 patient did not awake from the postoperative coma and needed tracheostomy. One zone 1 patient with massive stroke died of multiple organ failure, probably caused by multiple embolization, on the sixth postoperative day. Another zone 1 patient almost recovered from the hemiparesis before discharge. After the brain protection method was introduced, 2 patients experienced postoperative spinal cord injury (Zone 1, n = 1 and Zone 2, n = 1). In the zone 1 case, preoperative CT showed severe atheroma (Grade IV) from the proximal neck of the arch to the distal descending aorta. Extensive coverage of the downstream aorta was required to exclude the aneurysm. The zone 2 patient had previously undergone abdominal aortic replacement. Although the procedure was performed uneventfully, her postoperative haemodynamics were unstable due to postoperative retroperitoneal haemorrhage, which was the access site for TEVAR. She then developed delayed paraparesis. Early endoleaks were assessed by performing intraoperative aortography and/or MDCT before discharge. Type Ia endoleak and type Ib endoleak were 2% (n = 2) and 2% (n = 2), respectively. Type III endoleak did not occur. One patient with type Ia endoleak was successfully treated with open surgical repair. Another type Ia endoleak case was followed without additional intervention due to his severe comorbidities, and he died of aneurysm rupture 2 months after the surgery. Two type Ib endoleak cases were successfully treated with additional TEVAR.
Assessment of the risk factors for stroke Table 4 summarizes the covariates and stroke prevalence with 95% confidence intervals before the brain protection method was
Table 3: Early outcomes
Operation time (min) Thirty-day death In-hospital death Stroke Spinal cord injury Prolonged mechanical ventilation Acute coronary syndrome Extubation in the operation room Home discharge Endoleak Ia Ib II III
Total
Protection (−)
Protection (+)
P-value
178 ± 65 1 (1%) 2 (2%) 3 (3%) 2 (2%) 2 (2%) 2 (2%) 90 (89%) 91 (90%)
181 ± 69 1 (2%) 2 (4%) 3 (6%) 0 2 (4%) 2 (4%) 46 (87%) 47 (89%)
175 ± 63 0 0 0 2 (4%) 0 0 44 (92%) 44 (92%)
0.63 1.00 0.50 0.24 0.22 0.50 0.50 0.53 0.74
2 (2%) 2 (2%) 9 (9%) 0
1 (2%) 2 (4%) 7 (13%) 0
1 (2%) 0 2 (4%) 0
1.00 0.50 0.16 –
Protection (−): patients without the brain protection method. Protection (+): patients with the brain protection method.
T. Shijo et al. / European Journal of Cardio-Thoracic Surgery
5
Age
