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Repair of descending thoracic aortic aneurysms with Ankura Thoracic Stent Graft
Repair of descending thoracic aortic aneurysms with Ankura Thoracic Stent Graft Theodoros Kratimenos, MD, MSc,a Constantine N. Antonopoulos, MD, MSc, PhD, FEBVS,b Dimitrios Tomais, MD, MSc,a Panagiotis Dedeilias, MD, MSc, PhD, FETCS,b Vasileios Patris, MD, MSc,b Ilias Samiotis, MD, MSc,b John Kokotsakis, MD, MSc, PhD, FETCS,b Dimosthenis Farsaris, MD,a and Michalis Argiriou, MD, MSc, PhD, FETCS,b Athens, Greece
ABSTRACT Objective: The aim of the study was to present the results for patients with atherosclerotic aneurysm of the descending thoracic aorta (DTA) treated with a novel thoracic stent graft. Methods: A single-center retrospective review of prospectively collected data was performed. We extracted demographic variables as well as atherosclerotic comorbidities and operation-related and imaging-related data from patients’ medical records. We estimated technical success rate, in-hospital and 30-day mortality, and mortality at the end of follow-up as well as complication and reintervention rate in our study cohort. Follow-up computed tomography angiography was performed after 1 month and 6 months and yearly thereafter. Results: A total of 30 patients (80% male; mean age, 73.7 6 6.33 years) were treated with Ankura Thoracic Stent Graft (Lifetech, Shenzhen, China) for DTA aneurysm from February 2014 until June 2017. Technical success of the thoracic endovascular aortic repair (TEVAR) was 97% (29/30 patients). A surgical conduit was required in one patient; in three patients, we intentionally covered the left subclavian artery because of insufficient proximal landing zone. No aortarelated deaths were recorded during follow-up. During the early postoperative period, two patients (7%) with long DTA coverage developed paralysis or paraparesis, which immediately resolved after lumbar drainage. No renal complications requiring dialysis were observed. One patient (3%) developed postoperative pulmonary infection, whereas access site complications were 7%. Two symptomatic patients treated outside instructions for use (7%) developed early type IA endoleak and one patient (3%) developed type IB endoleak; type II endoleak was recorded in 3% of the study cohort. During the 30-day postoperative period, two patients died of non-TEVAR-related causes, one of gastrointestinal bleeding and the other of pulmonary infection. During a median follow-up of 31.7 (range, 38.4) months, two more patients also died of non-TEVAR-related causes, one of stroke from carotid artery disease and the other of motor vehicle trauma. In the rest of the cohort, no other adverse events were noted. Conclusions: This novel endograft showed early evidence of a safe, effective, and durable endoprosthesis for the treatment of DTA aneurysms. (J Vasc Surg 2018;-:1-7.) Keywords: Ankura; Thoracic; Aneurysm; Results
The incidence of degenerative atherosclerotic aneurysms in the descending thoracic aorta (DTA) is estimated to be approximately 6 to 10.4 cases per 100,000 person-years. Medial degeneration, with disruption and loss of elastic fibers and increased deposition of proteoglycans, with or without atherosclerosis, is the main histopathologic pattern of the disease.1 Interestingly, its
From the Department of Radiology, Interventional Radiology Unit,a and Department of Cardiothoracic and Vascular Surgery,b Evangelismos General Hospital of Athens. Author conflict of interest: none. Additional material for this article may be found online at www.jvascsurg.org. Correspondence: Constantine N. Antonopoulos, MD, MSc, PhD, FEBVS, Department of Cardiothoracic and Vascular Surgery, Evangelismos General Hospital of Athens, 45-47 Ipsilantou St, 105 51 Athens, Greece (e-mail: kostas. [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 2018 by the Society for Vascular Surgery. Published by Elsevier Inc. https://doi.org/10.1016/j.jvs.2018.07.065
clinical impact has had an incremental increase mainly because of the aging of the general population and partly because of the evolution of modern crosssectional imaging diagnostic methods (multislice computed tomography [CT] and magnetic resonance imaging).2,3 Current indications for repair use a diameter threshold of 60 mm for men and 55 mm for women but also a rate of expansion of >10 mm/y. Although a diameter of 60 mm carries an annual risk of rupture of 10%, the prognosis of larger degenerative aneurysms (>60 mm in diameter) is poor if they are not treated, with a 3-year survival of approximately 20%.4,5 With evolving endovascular techniques, even high-risk patients are now treated by endovascular means in an increasing number of cases. Thoracic endovascular aortic repair (TEVAR) has allowed a minimally invasive approach and has become the mainstay for treatment of DTA aneurysms. The aim of our study was to present characteristics and early outcomes of a newly introduced thoracic endograft, Ankura Thoracic Stent Graft (Lifetech, Shenzhen, China), for the treatment of DTA aneurysms. 1
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METHODS Study population. A retrospective review of prospectively collected data for all patients treated with Lifetech Ankura Thoracic Stent Graft for degenerative thoracic aortic aneurysms in our department from February 2014 until June 2017 was performed. Inclusion criteria included patients with fusiform or saccular atherosclerotic DTA aneurysm extending from zone 2 to zone 5. Ruptured aneurysms, symptomatic patients (chest discomfort; symptoms of surrounding organ compression, including dyspnea, dysphagia, shortness of breath, and hemoptysis), and patients with DTA aneurysm diameter >55 mm were treated. Patients with expanding DTA aneurysm diameter by >1 cm/y were also included in the study cohort. Patients with aortic dissection were excluded. Exclusion criteria also included patients with inadequate diameter of the access vessels for endovascular procedures, highly calcified femoral-iliac arteries, occluded or impossible to cross iliac stenoses, severe allergy to contrast media, any active infection, aneurysms with insufficient or nonhealthy proximal or distal thoracic aortic landing zone, and aortic diameter >42 mm at the level of the landing zones. Our initial intention was to use all proper anatomic criteria according to Ankura Thoracic Stent Graft instructions for use (IFU). All patients treated outside of these criteria were also included in our cohort. Informed consent from each patient and Institutional Review Board permission were obtained. Ankura Thoracic Stent Graft characteristics and IFU. The Ankura Thoracic Stent Graft is preloaded in a kinkresistant delivery system with hydrophilic coating indicated for endovascular repair of patients with thoracic aortic aneurysms. Among its novel characteristics compared with other commercially available endografts are the dual-layer expanded polytetrafluoroethylene membrane, the absence of suture on the main body that minimizes pinhole leakage, the asymmetric wave design, the proximal mini-wave stent, its special design for precise localization, and the need for neck length $1.5 cm. The endograft’s IFU indicate the need for an adequate iliac or femoral access vessel that is compatible with the required delivery system, nonaneurysmal aortic proximal neck length $1.5 cm, nonaneurysmal aortic distal anchorage zone $1.5 cm, nonaneurysmal aortic diameter in the range of 18 to 42 mm, and morphology suitable for endovascular repair. Additional considerations for selection of patients include the patient’s age and life expectancy, comorbidities (eg, cardiac, pulmonary, or renal insufficiency before surgery; morbid obesity), and tolerance of anesthesia (general, regional, or local). Device selection. The size of the Ankura stent graft should be appropriate to fit the patient’s aortic anatomy. Lifetech recommends an oversizing of the Ankura stent graft of 10% to 20% to the landing zone vessel’s inner diameter.
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ARTICLE HIGHLIGHTS d
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Type of Research: Retrospective analysis of prospectively collected cohort data Take Home Message: Thoracic endovascular aortic repair of descending thoracic aorta aneurysm with the Ankura Thoracic Stent Graft in 30 patients resulted in a technical success rate of 97%, paraparesis or paraplegia in two patients, late type IA endoleak in two patients, and no aorta-related deaths at a median follow-up of 31.7 months. Recommendation: This study suggests that the Ankura stent graft at 3 years is a safe and effective device for treatment of descending thoracic aortic aneurysms.
Contraindications. The Ankura stent graft is contraindicated in patients with acute systemic infection, patients with mesenteric blood flow mainly supplied by the inferior mesenteric artery, patients who have an allergic reaction to the device, patients who are not suitable for endovascular repair in vascular morphology, patients who cannot tolerate contrast agents because of renal insufficiency, and patients who are allergic to contrast agents. It is also contraindicated by aneurysm neck with thrombus, nonaneurysmal aortic proximal neck length <1.5 cm, nonaneurysmal aortic distal anchorage zone <1.5 cm, and nonaneurysmal aortic diameter <18 mm or >42 mm. Selection of patients. The safety and effectiveness of the Ankura Thoracic Stent Graft have not yet been evaluated in the following populations: patients with traumatic aortic injury; patients with uncorrectable coagulopathy; patients with hereditary connective tissue disease (eg, Marfan and Ehlers-Danlos syndromes); patients with active systemic infections; pregnant or nursing women; morbidly obese patients; patients younger than 18 years; and patients with life expectancy <1 year. Access vessel diameter (measured inner wall to inner wall) and morphology (minimal tortuosity, occlusive disease, and calcification) should be compatible with vascular access techniques and the profile of the delivery system. Vasculature that is too tortuous may increase the failure of stent graft deployment or proximal end release. The Ankura Thoracic Stent Graft is also not recommended in patients who weigh >350 pounds (150 kg) or cannot undergo accurate fluoroscopy examination because of obesity. Patients with a systemic infection may be at increased risk of endovascular stent graft infection. Furthermore, patients with uncorrectable coagulopathy may have an increased risk of type II endoleak or bleeding complications.
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Endovascular technique. Chest and abdominal CT angiography was performed in every patient before the endovascular procedure. All post-CT angiography images were transferred to a dedicated software workstation to obtain preoperative measurements. A multidisciplinary team, including cardiac and vascular surgeons and interventional radiologists, discussed and planned each case on an individual basis. All TEVAR interventions were performed in the angiography suite, equipped with an Innova angiographic system (GE Healthcare, Wauwatosa, Wisc). The angiography suite is also equipped with a complete anesthesia system with the potential for real-time full monitoring of the patient. Each patient was placed in the supine position. Both groins and the right or left arm in case the preoperative plan indicated potential use of the brachial artery were prepared and draped. Local anesthesia along with light sedation (general or regional anesthesia) was used. Spinal drainage before TEVAR was not routinely used; however, lumbar drainage was readily available in the angiography suite, and an experienced neurosurgeon was available in cases of previous aortic surgery when coverage of the subclavian artery was planned or when extensive coverage (ie, more than two-thirds) of the DTA by the stent graft was required. Our spinal cord protection protocol included maintaining an adequate mean systemic pressure during the procedure and during the recovery period and close neurologic monitoring for 48 hours after the procedure. In case of need for spinal drainage in symptomatic patients, spinal pressures <10 mm Hg were maintained for 48 hours, after which spinal catheters were removed. A broadspectrum antibiotic was administered, a femoral artery cutdown was performed on the device access site, and the patient received 5000 units of heparin. After the initial advancement of a vertebral 5F angiocatheter in the ascending aorta, a curved, extrastiff wire (Lunderquist; Cook Medical, Bloomington, Ind) was placed in the ascending aorta through this catheter. The contralateral femoral artery or the left (usually) brachial artery was punctured, and a pigtail catheter was placed under fluoroscopic guidance in the ascending aorta through a 5F sheath to perform aortography. The stent graft was prepared and advanced into the correct position on the basis of the previously obtained angiogram in the left anterior oblique projection (usually 40-45 degrees) for arch vessels and lesion mapping. The endograft comes with a delivery system with outer diameter of 18F to 24F. The endografts used in our case were mainly mounted in 21F to 24F delivery systems. Oversizing by 15% to 20% was used, according to the preoperative plan. Confirmatory aortography was performed and slight adjustments were made. Blood pressure was brought down to approximately 100 mm Hg, the device was deployed (Supplementary Fig 1, online only), and then a remodeling balloon was used (if necessary) under
fluoroscopy. Although the endograft’s IFU do not impose the routine use of endograft ballooning, a molding balloon was used selectively in cases of multiple stent grafts at the seal zones and at any overlap zones to ensure full apposition to the aortic wall when needed. The left subclavian artery was intentionally occluded in some cases to extend the proximal landing zone. In these cases, angiography was initially performed to verify the position and the patency of the left vertebral artery. Coverage of the subclavian artery without revascularization is generally well tolerated, and our team has decided to proceed without routine carotid-subclavian bypass unless the patient had prior internal mammary artery grafting. All patients were assessed for arm claudication or fatigue on follow up. After the endograft’s deployment, final angiography was then performed to assess potential endoleak. Femoral artery cutdown was sutured with 6-0 Prolene, and the wound incision was closed. After TEVAR, the patients remained in the main cardiovascular ward. All patients were discharged under single antiplatelet therapy unless contraindicated. Follow-up CT scan was performed after 1 month and 6 months and yearly thereafter. Statistical analyses. Continuous variables (Supplementary Methods, online only) were expressed as mean 6 standard deviation or median (range). Categorical variables (Supplementary Methods, online only) were expressed as proportions (percentage). All outcome rates were appropriately calculated as the ratio of events within the designated population of respective cases. Kaplan-Meier analysis was performed to obtain estimates and 95% confidence intervals of freedom from reintervention. Stata statistical software (version 12.0; StataCorp LP, College Station, Tex) was used for the analysis.
RESULTS Cohort of patients. A total of 30 nonconsecutive patients (80% male; mean age, 73.7 6 6.33 years) with DTA aneurysms were treated with Ankura Thoracic Stent Graft during the study period in our department. Baseline atherosclerotic characteristics of the cohort are shown in Table I. Among them, hypertension (57%), smoking habit (70%), and hyperlipidemia (50%) were highly prevalent. Half of our study cohort patients were treated on an elective basis; seven patients (23%) presented with rupture (Table II). One patient (3%) had a history of prior endovascular aneurysm repair. Procedure-related characteristics. Local anesthesia with light sedation was used in most of the treated patients (n ¼ 29; 97%); only one patient required general anesthesia (3%) because of the requirement for a surgical conduit (Table II). Mean duration of the TEVAR procedure was 114.5 6 38.4 minutes; dose-area product was 313.1 6 228.3 dGy cm2, and we used fluoroscopy for
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Table I. Baseline characteristics of the patients (N ¼ 30) Age, years, mean (SD)
73.7 (6.3)
Male sex
24 (80)
Hypertension
17 (57)
Diabetes mellitus
5 (17)
Hyperlipidemia
15 (50)
Smoking (present or past)
21 (70)
Coronary artery disease
8 (27)
Previous myocardial infarction
4 (13)
Arrhythmias
5 (17)
Peripheral artery disease
7 (23)
Chronic renal failure
4 (13)
Previous neurologic event
2 (7)
Chronic obstructive pulmonary disease
7 (23)
SD, Standard deviation. Values are reported as number (%) unless otherwise indicated.
Table II. Operation-related characteristics (N ¼ 30) Clinical symptoms Elective repair
15 (50)
Symptomatic DTA aneurysm
8 (27)
Ruptured DTA aneurysm
7 (23)
Type of prior aortic treatment None
29 (97)
EVAR
1 (3)
Type of anesthesia used Local
29 (97)
General
1 (3)
Technical success
29 (97)
Duration of operation, minutes Fluoroscopy time, minutes Dose-area product, dGy cm
114.5 (38.4) 12.9 (6.2)
2
313.1 (228.3)
Contrast material administered, mL
202.3 (55.4)
Blood loss, mL
272.3 (149.4)
Length of hospital stay, days
4.3 (2.9)
DTA, Descending thoracic aorta; EVAR, endovascular aneurysm repair. Categorical variables are presented as number (%). Continuous variables are presented as mean (standard deviation).
12.9 6 6.2 minutes. The mean contrast material volume administered was 202.3 6 55.4 mL, whereas blood loss was estimated at 272.3 6 149.4 mL. Only one patient (3%) needed transfusion at the end of the procedure because of a low preoperative hemoglobin level. All patients were discharged after a mean of 4.3 6 2.9 days. DTA characteristics and technical details of the procedure. Technical success of the procedure was 97% (29/ 30 patients). One patient required a surgical conduit in the common iliac artery because of small diameter and heavily calcified femoral arteries. The sole patient with technical failure had a successful initial delivery of the
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endograft into the correct aortic position, but the deployment was unsuccessful, probably because of the extreme tortuosity of the DTA (Supplementary Fig 2, online only). The device was kinked and we could not unsheathe the endograft. The whole device was thereafter retrieved from the aorta. In this same patient, a second device of a different commercial type was used, which also failed to overcome the kinked aorta, and finally the case was abandoned. As shown in Table III, among the 29 patients with successful endograft implantation, the maximum diameter of the DTA was 73 6 1.5 mm. Proximal landing zone of the stent graft was zone 2 in 3 cases (10%), with a mean diameter of 33 6 3.5 mm, and zone 3 in the remaining 26 patients (90%), with a mean diameter of 34 6 4.4 mm. Distally, endografts were landed in zone 4 and 5 in 28 patients (97%; mean diameter, 34 6 3.5 mm and 32 6 3.5 mm, respectively) and in zone 6 in one patient (3%; diameter, 32 mm). We used the common femoral artery as the main access vessel in 28 patients (97%), whereas 1 patient required a surgical conduit, as reported previously. A total of 15 patients (52%) required only one stent graft; in 11 patients (38%), a second stent graft was necessary; and in 3 patients (10%), three stent grafts were used for appropriate sealing. We covered the left subclavian artery without any additional procedure in three patients (10%) because of insufficient proximal landing zone, with no postoperative complication. Early (30-day/in-hospital) follow-up. During the early follow-up, two (7%) access site complications were recorded, mainly small hematoma and serous collection, which did not require any operation (Table IV). Apart from one patient (3%) who developed a postoperative pulmonary infection, no other major adverse event, including cerebral, cardiac, or renal complication requiring dialysis, was observed. A total of two patients (7%) developed early postoperative paralysis or paraparesis, which immediately resolved after lumbar drainage. One patient (3%) died while in the hospital of gastrointestinal bleeding; another patient died during the first 30 days after the procedure of sepsis after pulmonary infection. Late (post-30-day/in-hospital) follow-up. A 10% (n ¼ 3) type I endoleak rate was recorded during follow-up. More specifically, two patients (7%) developed type IA (proximal) and one patient (3%) developed type IB (distal) endoleak. The patient with type IB endoleak was reoperated on after the first follow-up CT scan (1 month), and coverage of the celiac trunk with a stent graft was required because of short distal landing zone. Since then and during follow-up, the patient has not developed any kind of endoleak; the branches of the celiac trunk are supplied through the superior mesenteric artery collaterals. Of the two patients with type IA endoleak, one was
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Table III. Aorta-related and technical characteristics among patients with successful endograft implantation (N ¼ 29)
Table IV. Outcomes among patients with successful endograft implantation during follow-up, including 30-day/in-hospital outcomes (N ¼ 29)
Maximum diameter of DTA, mm
Variables
73 (1.5)
Proximal diameter of DTA, mm
Access site complications
Zone 2
33 (3.5)
Endoleak
Zone 3
34 (4.4)
Type I
Distal diameter of DTA, mm
Type II
No. (%) 2 (7) 3 (10) 1 (3)
Zone 4
34 (3.5)
Cerebral complications
1 (3)
Zone 5
32 (3.6)
Cardiac complications
0 (0)
Paralysis or paraparesis
2 (7)
Proximal landing zone Zone 2
3 (10)
Zone 3
26 (90)
Distal landing zone Zone 4-5 Zone 6
28 (97) 1 (3)
Access site Femoral Other
28 (97) 1 (3)
Pulmonary complications
1 (3)
Renal failure requiring dialysis
0 (0)
Retroaortic type A dissection
0 (0)
In-hospital mortality
1 (3)
Aorta-related mortality
0 (0)
30-Day mortality
2 (7)
Reinterventions
3 (10)
Mortality at end of follow-up
4 (14)
No. of stent grafts used 1
15 (52)
2
11 (38)
3 Coverage of left subclavian artery
3 (10) 3 (10)
DTA, Descending thoracic aorta. Categorical variables are presented as number (%). Continuous variables are presented as mean (standard deviation).
successfully reoperated on with a new, proximally implanted endoprosthesis. The second patient refused any reoperation; however, his CT scan images at 6 months and 1 year of follow-up showed partial thrombosis of the aneurysm sac with no increase in its diameter (5.5 cm since the beginning). One patient (3%) was diagnosed with type II endoleak at the 6-month follow-up CT examination, and he was treated with implantation of a vascular plug at the orifice of the left subclavian artery. As a result, the reintervention rate in our cohort was 10% (3/29). Kaplan-Meier analysis with estimates and 95% confidence intervals of freedom from reintervention are provided in the Fig. No aorta-related death was observed. One patient died 2 months after operation of H1N1 influenza acute respiratory distress syndrome. During a median follow-up of 31.7 (range, 38.4) months, two more patients died of non-TEVAR-related causes, one of stroke from carotid artery disease, in whom the left subclavian artery was not covered, and the other of motor vehicle trauma. In the rest of the cohort, no other adverse events were recorded.
DISCUSSION This cohort consisted of 30 patients with thoracic aortic aneurysms treated with the Ankura Thoracic Stent Graft. Technical success was high at 97%, with only one failure
Fig. Kaplan-Meier analysis with estimates and 95% confidence intervals (CIs) of freedom from reintervention.
outside of IFU due to high tortuosity of the DTA in a patient at high risk for open surgery. Safety and efficacy of the endograft were documented as we did not record any serious major adverse events; the two cases of spinal cord ischemia were immediately resolved with lumbar drainage, leaving no permanent effect. A 7% rate of proximal endoleak was recorded in symptomatic patients with short proximal neck; however, apart from one patient who refused further treatment, all endoleaks were successfully sealed with simple early endovascular reinterventions. Endovascular repair of DTA has been proved to be relatively safe and has been demonstrated to be effective in preventing aortic rupture. Our study showed satisfactory
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early outcomes, comparable to outcomes reported by large studies of already established thoracic endografts. Among these studies, the GORE TAG (W. L. Gore & Associates, Flagstaff, Ariz) endoprosthesis was the first DTA device to enter phase 2 trials in the United States. In a cohort of 139 patients, the device was successfully implanted in 98% of the patients. Early 30-day results demonstrated a 1.5% mortality rate, 4% stroke rate, and 3% temporary or permanent paraplegia and 9% bleeding complications. During a 24-month follow-up, 2.9% aneurysm-related mortality was recorded, whereas no aortic ruptures occurred. Interestingly, the authors reported 20 wire fractures in 19 patients, of which only 1 required treatment.6 At 5 years, aneurysm-related mortality for TAG patients was 2.8%. Endoleaks decreased from 8.1% at 1 month to 4.3% at 5 years, whereas major aneurysm-related reinterventions at 5 years were 3.6%.7 During the 5-year follow-up of the TAG endograft, there have been no ruptures, one migration, and no collapse; after revision of the endograft into the modified lowporosity device at 24 months, sac increase was detected in 12.9% of the original vs 2.9% of the modified grafts.7 In another study, Zenith TX1 and TX2 (Cook Medical, Bloomington, Ind) devices for TEVAR proved to have durable outcomes, with aneurysm-related survival being 91.7% at 5 years.8 Freedom from any endoleak was 77.8%, 77.2%, 72.2%, and 62.3% at 1 year, 2 years, 5 years, and 9 years, respectively. Zenith TX2 was also evaluated by another study,9 showing endoleak in 3.9% and migration in 2.8% at 12 months. None of the patients had stent fracture, barb separation, stent to graft separation, or component separation. The authors reported 2.5% stroke, 1.3% paraplegia, and 4.4% paraparesis rate occurring before the first 30 days after TEVAR.9 Moreover, Zenith Alpha (Cook Medical) endograft also evidenced great results in a study of 70 TEVAR patients.10 During the <2-year mean follow-up, the authors reported no conversions to open repair and no ruptures or intraoperative deaths. A 4.3% and 2.9% rate of type IA and type IB endoleak, respectively, with no type III or type IV endoleak was recorded. There was one case of distal stent graft migration and no stent fracture; reintervention was necessary in only 1.4% of the study cohort. The Evaluation of the Medtronic Vascular Talent Thoracic Stent Graft System for the Treatment of Thoracic Aortic Aneurysms (VALOR) trial also enrolled 195 TEVAR patients. Freedom from aneurysm-related mortality was 96.9% at 1 year and 96.1% at 5 years; endoleak type I and type III occurred in 4.6% and 1.3% of the study population at 1 month, respectively. Through the 5-year follow-up, 14.4% of the patients underwent additional endovascular procedures on the original target lesion. Stent graft migration was noted in 0.6% in the first year.11 The VALOR II trial enrolled 160 patients with higher rates of cardiovascular risk factors and significantly more severe modified Society for Vascular Surgery/American
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Association for Vascular Surgery risk scores compared with the VALOR trial. Outcomes at 30 days were 3.1% perioperative mortality, 0.6% paraplegia, 1.9% paraparesis, and 2.5% stroke.12 In the Bolton Relay Thoracic Aortic Endovascular Pivotal Trial,13 which enrolled 120 patients, thoracic endografts were delivered and deployed in 97.0% of the study sample. The authors reported a 30-day mortality rate of 5.3%. At 5 years, freedom from aneurysmrelated mortality was 91.3%. Type I or type III endoleak was 4.5%, whereas in 7.5% of the patients, secondary procedures were required to correct the endoleak. The study detected a 2.3% endograft migration rate, with 1.5% wire form fracture rate. Modifications to the original delivery system led to improved outcomes with uniform technical success, no instances of endoleak and migration or fracture, and a significant decrease in strokes (2.6% vs 12.6% with the original endograft).13 Finally, putting evidence together, a recent meta-analysis14 collected data from 11 studies reporting on 673 patients treated with TEVAR for DTA aneurysm. Technical success was 91.0% of patients, with pooled overall 30-day and 3-year survival rates at 96.0% and 74.0%, respectively. Paraplegia occurred in 3.2% of patients and was permanent in 1.4% of patients, whereas the stroke rate was 2.7%. The authors reported 7.3% early type I endoleak, with type II endoleak in 2.0% and type III in 1.2% of the patients. Freedom from reintervention was 90.3% at the end of follow-up.14 The most important strength of our study is the firstever reported results of a new thoracic endograft with strict inclusion criteria concerning the aortic disease. However, our study has some limitations that should also be addressed. First, the number of study participants is lower compared with the already published big series for other endografts, thus making direct comparison of results difficult. Furthermore, the selection of patients was made on an individual patient basis, and as result, this might have introduced a potential selection bias. Moreover, although this is a retrospective review of prospectively collected data, it lacks a control group composed of TEVAR patients treated with other commercially available endografts or open repair patients, which would be ideal in terms of comparing the results. What is more, this series represents a “reallife” single-center experience, and therefore results should be confirmed by future high-volume multicenter, prospective studies. Last, our follow-up period is not long enough, making long-term durability of the endograft unexplored.
CONCLUSIONS The Ankura Thoracic Stent Graft seems to provide a safe, effective, and durable endoprosthesis for the treatment of atherosclerotic thoracic aortic aneurysms. It showed a 0% aneurysm-related mortality during
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follow-up and low endoleak and overall complication rate. However, the long-term durability of the endograft should be tested after a longer follow-up period.
AUTHOR CONTRIBUTIONS Conception and design: TK, CA, DT, PD, VP, IS, JK, DF, MA Analysis and interpretation: TK, CA, DT, MA Data collection: TK, DT Writing the article: TK, CA Critical revision of the article: TK, CA, DT, PD, VP, IS, JK, DF, MA Final approval of the article: TK, CA, DT, PD, VP, IS, JK, DF, MA Statistical analysis: CA Obtained funding: Not applicable Overall responsibility: CA TK and CA contributed equally to this article and share co-first authorship.
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6. Makaroun MS, Dillavou ED, Kee ST, Sicard G, Chaikof E, Bavaria J, et al. Endovascular treatment of thoracic aortic aneurysms: results of the phase II multicenter trial of the GORE TAG thoracic endoprosthesis. J Vasc Surg 2005;41:1-9. 7. Makaroun MS, Dillavou ED, Wheatley GH, Cambria RP; Gore TAG Investigators. Five-year results of endovascular treatment with the Gore TAG device compared with open repair of thoracic aortic aneurysms. J Vasc Surg 2008;47:912-8. 8. Beach JM, Kuramochi Y, Brier C, Roselli EE, Eagleton MJ. Durable outcomes of thoracic endovascular aortic repair with Zenith TX1 and TX2 devices. J Vasc Surg 2017;65:1287-96. 9. Matsumura JS, Cambria RP, Dake MD, Moore RD, Svensson LG, Snyder S, et al. International controlled clinical trial of thoracic endovascular aneurysm repair with the Zenith TX2 endovascular graft: 1-year results. J Vasc Surg 2008;47:247-57; discussion: 257. 10. Torsello GF, Inchingolo M, Austermann M, Torsello GB, Panuccio G, Bisdas T. Durability of a low-profile stent graft for thoracic endovascular aneurysm repair. J Vasc Surg 2017;66:1638-43. 11. Foley PJ, Criado FJ, Farber MA, Kwolek CJ, Mehta M, White RA, et al. Results with the Talent thoracic stent graft in the VALOR trial. J Vasc Surg 2012;56:1214-21.e1. 12. Fairman RM, Tuchek JM, Lee WA, Kasirajan K, White R, Mehta M, et al. Pivotal results for the Medtronic Valiant Thoracic Stent Graft System in the VALOR II trial. J Vasc Surg 2012;56:1222-31.e1. 13. Farber MA, Lee WA, Szeto WY, Panneton JM, Kwolek CJ. Initial and midterm results of the Bolton Relay Thoracic Aortic Endovascular Pivotal Trial. J Vasc Surg 2017;65: 1556-66.e1. 14. Biancari F, Mariscalco G, Mariani S, Saari P, Satta J, Juvonen T. Endovascular treatment of degenerative aneurysms involving only the descending thoracic aorta: systematic review and meta-analysis. J Endovasc Ther 2016;23:387-92.
Submitted Mar 31, 2018; accepted Jul 26, 2018.
Additional material for this article may be found online at www.jvascsurg.org.
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SUPPLEMENTARY METHODS (online only). Variables of interest extracted from patients’ medical records. Preoperative factors extracted from the patients’ medical records included age, sex, atherosclerotic comorbidities (hypertension, diabetes mellitus, hypercholesterolemia, history of smoking, coronary artery disease, previous myocardial infarction, any arrhythmias, peripheral artery disease, chronic renal failure, previous neurologic event, chronic obstructive pulmonary disease), and any connective tissue disorder. Operationrelated characteristics included clinical symptoms, type of prior aortic treatment, type of anesthesia used, duration of operation, fluoroscopy time, dose-area product, volume of contrast material administered, volume of blood loss, and length of hospital stay. We also extracted aorta-related characteristics, including the proximal, distal, and maximum diameter of the descending thoracic aorta (DTA), the access site, the number of stent grafts used, the percentage of patients who needed coverage of the left subclavian artery, and the type of concomitant procedure when needed. We defined technical success as the successful and accurate deployment of the stent graft after any additional intraoperative procedure when necessary. We collected data about the 30-day and follow-up outcomes, including presence of access site complication, endoleak of any type, neurologic event, myocardial infarction, paralysis or paraparesis, pulmonary complication, renal failure, retroaortic type A dissection, and any reintervention. We estimated the 30-day and in-hospital mortality as well as aorta-related mortality, and we also recorded follow-up. The Ankura Thoracic Stent Graft (Lifetech, Shenzhen, China) is a self-expanding straight or tapered endoprosthesis made of an expanded polytetrafluoroethylene (ePTFE) dual membrane that contains sinusoidal selfexpanding nitinol springs. There is no suture on the main body to avoid pinhole leakage and thus to provide better biocompatibility and durability. The sinusoidal shape and placement of the self-expanding nitinol springs also provide flexibility and conformability in the stent graft, exerting radial force to enhance seal and fixation. The stent graft is premounted into a low-profile (21F-24F) delivery system with hydrophilic coating that is kink resistant to facilitate the delivery in tortuous and atherosclerotic arteries. Interestingly, after graft deployment and before tip capture release, it is still possible to make small final positional adjustments because of the nitinol scaffolding, which is internal to the double ePTFE membrane. The first nitinol spring strut has shorter length compared with the rest of the nitinol springs. This provides optimal fixation with enhanced apposition to the aortic wall and efficient conformability, especially in angulated necks, decreasing the possibility of endoleak and preventing the risk of migration. The proximal part
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of the stent graft is provided with a fixation system of six bare stents that distribute the radial force over multiple apices. This allows the deployment over the left subclavian artery or even the left common carotid artery without occluding the blood flow, thus providing an extended proximal landing zone. Another unique characteristic is that the proximal bare stents are embedded in the stent graft to be less traumatic, providing a clear advantage in case of traumatized aortic wall, such as in dissections. The proximal barbs remain covered by the clasping system until complete deployment, whereas the distal part of the graft has a closed web configuration. The stent graft is also provided with a longitudinal supporting bar on the greater curvature, which prevents shortening and provides axial support. To optimize the graft’s sealing, there is no bar in the first and last nitinol spring strut. The Ankura Thoracic Stent Graft comes with two radiopaque markers in its proximal covered part. The first is a “figure 8”-shaped marker placed at the greater curvature, and the second is a “figure 0”-shaped marker at the lesser curvature. Both provide high visibility and assist in accurate graft orientation and deployment. The deployment process is easy and specially designed to be operator friendly as the delivery system is provided with a two-handle system; the front handle must be kept fixed with the operator’s left hand while the second handle is being rotated clockwise by the operator’s right hand, allowing a slow and controlled deployment of the graft. However, a fast deployment is also possible by pulling back a safety valve on the second handle. The operator is releasing the clasping system of the stent graft in two movements: first, by removing the safe buckle (green), then by pulling back the tip releaser (black). Finally, to keep the correct orientation during the advancement of the stent graft in the DTA, there is a side port at the delivery system of the endoprosthesis that must be oriented at the 3-o’clock position to keep the longitudinal bar toward the external curvature of the DTA. However, in some cases, because of the aorta’s tortuosity, small adjustments may be needed in the graft’s orientation; in this situation, the operator has to keep the figure 8 proximal marker at the external curvature of the DTA and the figure 0 marker at the aorta’s lesser curvature. Technical comparison of commercially available endografts. Lifetech Ankura Thoracic Stent Graft has the advantage of no suture on the main body, thus avoiding pinhole leakage, which may cause type IV endoleak, and it is preloaded in a kink-resistant delivery system with hydrophilic coating. Furthermore, it is specially designed, allowing precise localization, which is especially crucial in case of lack of proximal landing zone. Its flexibility is excellent because of the unique design of the “sandwich”-like structure, and the longitudinal supporting
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strut on the greater curvature avoids stent shortening and provides axial support. Among the various commercially available endografts, the TAG (W. L. Gore & Associates, Flagstaff, Ariz) endoprosthesis is a flexible nitinol-supported PTFE graft in which the exoskeleton is bonded to the graft material without sutures. The release of the constraining sleeve allows rapid deployment of the endograft and expansion from the middle of the endoprosthesis toward the ends of the graft, thus avoiding displacing forces of the high arterial flow when the device is partially deployed. The Zenith TX2 (Cook Medical, Bloomington, Ind) endovascular graft is a one- or two-piece tubular endoprosthesis constructed of full-thickness woven polyester fabric sewn to self-expanding stainless steel. Stability and the expansile force are achieved by the fully stented endograft; sealing is secured by the barbs at the distal and proximal ends. Contrary to the TAG endoprosthesis, the Zenith TX2 endograft is provided with a delivery system that allows staged and controlled placement in the often tortuous thoracic aorta.1 The newer generation Zenith Alpha (Cook Medical) thoracic stent graft features a tightly woven polyester graft, sewn to self-expanding nitinol stents with monofilament polypropylene sutures, that allows loading of the graft in low-profile delivery systems ranging between 16F and 20F.2 The Valiant (Medtronic, Santa Rosa, Calif) stent graft system is a modular, self-expanding, tubular endoprosthesis composed of a series of serpentine five-peaked springs stacked in a tubular configuration and compressed and preloaded in a single-use disposable catheter with an integrated handle. The endograft has eight-peak configuration in its proximal bare spring, intended to distribute the radial force across more points of contact, resulting in less force per point.3 Another commercially available endograft, the Relay (Bolton Medical, Sunrise, Fla) thoracic stent graft, is a modular device composed of self-expanding nitinol stents sutured to polyester fabric with a bare proximal stent and covered distal stent, and there is also a curved nitinol wire that provides longitudinal support. The unique characteristic of the endograft is that the connecting bars are not attached to the proximal sealing stent configuration. The endoprosthesis has a two-stage device deployment technique that facilitates navigation and alignment.4
Technical tips and overall operator’s impression of Lifetech Ankura endograft. d The device needs to be watered first from the back part of the delivery system and then from the lateral side port, and similar to other devices, the operator has to put in some force to bring out all possible air bubbles from the delivery system. d After this step, plenty of saline water needs to be spread over the hydrophilic part of the delivery system, and we suggest waiting a few seconds before use of the device to get the maximum hydrophilic effect. d There is no gap between the tip of the delivery system and the hydrophilic part of the delivery system, which permits the smooth advancement of the device through the femoral and iliac arteries if adequate artery diameter exists. d The delivery system is kink resistant and usually succeeds in overpassing even extreme aortic tortuosity. The graft is highly visible during fluoroscopy, and both proximal radiopaque markers (figure 0 and figure 8) are easily depicted. d The feeling during the graft’s deployment is of an accurate positioning graft, and we propose deployment of the first two nitinol springs, then proceeding with fast graft withdrawal. d As this is an e-PTFE graft, we advise avoiding the use of a remodeling balloon as in a few cases we noticed small graft migration after ballooning. d After graft deployment, resheathing of the tip was always uneventful, and even in very tortuous aortas, we managed to retrieve it by rotating the delivery system.
SUPPLEMENTARY REFERENCES 1. Matsumura JS, Cambria RP, Dake MD, Moore RD, Svensson LG, Snyder S, et al. International controlled clinical trial of thoracic endovascular aneurysm repair with the Zenith TX2 endovascular graft: 1-year results. J Vasc Surg 2008;47: 247-57; discussion: 257. 2. Torsello GF, Inchingolo M, Austermann M, Torsello GB, Panuccio G, Bisdas T. Durability of a low-profile stent graft for thoracic endovascular aneurysm repair. J Vasc Surg 2017;66: 1638-43. 3. Fairman RM, Tuchek JM, Lee WA, Kasirajan K, White R, Mehta M, et al. Pivotal results for the Medtronic Valiant Thoracic Stent Graft System in the VALOR II trial. J Vasc Surg 2012;56:1222-31.e1. 4. Farber MA, Lee WA, Szeto WY, Panneton JM, Kwolek CJ. Initial and midterm results of the Bolton Relay Thoracic Aortic Endovascular Pivotal Trial. J Vasc Surg 2017;65:1556-66.e1.
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Supplementary Fig 1 (online only). Device characteristics of Lifetech Ankura Thoracic Stent Graft.
Supplementary Fig 2 (online only). Digital subtraction angiography showing a case of tortuous aorta.
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ABSTRACT Objective: The aim of the study was to present the results for patients with atherosclerotic aneurysm of the descending thoracic aorta (DTA) treated with a novel thoracic stent graft. Methods: A single-center retrospective review of prospectively collected data was performed. We extracted demographic variables as well as atherosclerotic comorbidities and operation-related and imaging-related data from patients’ medical records. We estimated technical success rate, in-hospital and 30-day mortality, and mortality at the end of follow-up as well as complication and reintervention rate in our study cohort. Follow-up computed tomography angiography was performed after 1 month and 6 months and yearly thereafter. Results: A total of 30 patients (80% male; mean age, 73.7 6 6.33 years) were treated with Ankura Thoracic Stent Graft (Lifetech, Shenzhen, China) for DTA aneurysm from February 2014 until June 2017. Technical success of the thoracic endovascular aortic repair (TEVAR) was 97% (29/30 patients). A surgical conduit was required in one patient; in three patients, we intentionally covered the left subclavian artery because of insufficient proximal landing zone. No aortarelated deaths were recorded during follow-up. During the early postoperative period, two patients (7%) with long DTA coverage developed paralysis or paraparesis, which immediately resolved after lumbar drainage. No renal complications requiring dialysis were observed. One patient (3%) developed postoperative pulmonary infection, whereas access site complications were 7%. Two symptomatic patients treated outside instructions for use (7%) developed early type IA endoleak and one patient (3%) developed type IB endoleak; type II endoleak was recorded in 3% of the study cohort. During the 30-day postoperative period, two patients died of non-TEVAR-related causes, one of gastrointestinal bleeding and the other of pulmonary infection. During a median follow-up of 31.7 (range, 38.4) months, two more patients also died of non-TEVAR-related causes, one of stroke from carotid artery disease and the other of motor vehicle trauma. In the rest of the cohort, no other adverse events were noted. Conclusions: This novel endograft showed early evidence of a safe, effective, and durable endoprosthesis for the treatment of DTA aneurysms. (J Vasc Surg 2018;-:1-7.) Keywords: Ankura; Thoracic; Aneurysm; Results
The incidence of degenerative atherosclerotic aneurysms in the descending thoracic aorta (DTA) is estimated to be approximately 6 to 10.4 cases per 100,000 person-years. Medial degeneration, with disruption and loss of elastic fibers and increased deposition of proteoglycans, with or without atherosclerosis, is the main histopathologic pattern of the disease.1 Interestingly, its
From the Department of Radiology, Interventional Radiology Unit,a and Department of Cardiothoracic and Vascular Surgery,b Evangelismos General Hospital of Athens. Author conflict of interest: none. Additional material for this article may be found online at www.jvascsurg.org. Correspondence: Constantine N. Antonopoulos, MD, MSc, PhD, FEBVS, Department of Cardiothoracic and Vascular Surgery, Evangelismos General Hospital of Athens, 45-47 Ipsilantou St, 105 51 Athens, Greece (e-mail: kostas. [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 2018 by the Society for Vascular Surgery. Published by Elsevier Inc. https://doi.org/10.1016/j.jvs.2018.07.065
clinical impact has had an incremental increase mainly because of the aging of the general population and partly because of the evolution of modern crosssectional imaging diagnostic methods (multislice computed tomography [CT] and magnetic resonance imaging).2,3 Current indications for repair use a diameter threshold of 60 mm for men and 55 mm for women but also a rate of expansion of >10 mm/y. Although a diameter of 60 mm carries an annual risk of rupture of 10%, the prognosis of larger degenerative aneurysms (>60 mm in diameter) is poor if they are not treated, with a 3-year survival of approximately 20%.4,5 With evolving endovascular techniques, even high-risk patients are now treated by endovascular means in an increasing number of cases. Thoracic endovascular aortic repair (TEVAR) has allowed a minimally invasive approach and has become the mainstay for treatment of DTA aneurysms. The aim of our study was to present characteristics and early outcomes of a newly introduced thoracic endograft, Ankura Thoracic Stent Graft (Lifetech, Shenzhen, China), for the treatment of DTA aneurysms. 1
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METHODS Study population. A retrospective review of prospectively collected data for all patients treated with Lifetech Ankura Thoracic Stent Graft for degenerative thoracic aortic aneurysms in our department from February 2014 until June 2017 was performed. Inclusion criteria included patients with fusiform or saccular atherosclerotic DTA aneurysm extending from zone 2 to zone 5. Ruptured aneurysms, symptomatic patients (chest discomfort; symptoms of surrounding organ compression, including dyspnea, dysphagia, shortness of breath, and hemoptysis), and patients with DTA aneurysm diameter >55 mm were treated. Patients with expanding DTA aneurysm diameter by >1 cm/y were also included in the study cohort. Patients with aortic dissection were excluded. Exclusion criteria also included patients with inadequate diameter of the access vessels for endovascular procedures, highly calcified femoral-iliac arteries, occluded or impossible to cross iliac stenoses, severe allergy to contrast media, any active infection, aneurysms with insufficient or nonhealthy proximal or distal thoracic aortic landing zone, and aortic diameter >42 mm at the level of the landing zones. Our initial intention was to use all proper anatomic criteria according to Ankura Thoracic Stent Graft instructions for use (IFU). All patients treated outside of these criteria were also included in our cohort. Informed consent from each patient and Institutional Review Board permission were obtained. Ankura Thoracic Stent Graft characteristics and IFU. The Ankura Thoracic Stent Graft is preloaded in a kinkresistant delivery system with hydrophilic coating indicated for endovascular repair of patients with thoracic aortic aneurysms. Among its novel characteristics compared with other commercially available endografts are the dual-layer expanded polytetrafluoroethylene membrane, the absence of suture on the main body that minimizes pinhole leakage, the asymmetric wave design, the proximal mini-wave stent, its special design for precise localization, and the need for neck length $1.5 cm. The endograft’s IFU indicate the need for an adequate iliac or femoral access vessel that is compatible with the required delivery system, nonaneurysmal aortic proximal neck length $1.5 cm, nonaneurysmal aortic distal anchorage zone $1.5 cm, nonaneurysmal aortic diameter in the range of 18 to 42 mm, and morphology suitable for endovascular repair. Additional considerations for selection of patients include the patient’s age and life expectancy, comorbidities (eg, cardiac, pulmonary, or renal insufficiency before surgery; morbid obesity), and tolerance of anesthesia (general, regional, or local). Device selection. The size of the Ankura stent graft should be appropriate to fit the patient’s aortic anatomy. Lifetech recommends an oversizing of the Ankura stent graft of 10% to 20% to the landing zone vessel’s inner diameter.
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ARTICLE HIGHLIGHTS d
d
d
Type of Research: Retrospective analysis of prospectively collected cohort data Take Home Message: Thoracic endovascular aortic repair of descending thoracic aorta aneurysm with the Ankura Thoracic Stent Graft in 30 patients resulted in a technical success rate of 97%, paraparesis or paraplegia in two patients, late type IA endoleak in two patients, and no aorta-related deaths at a median follow-up of 31.7 months. Recommendation: This study suggests that the Ankura stent graft at 3 years is a safe and effective device for treatment of descending thoracic aortic aneurysms.
Contraindications. The Ankura stent graft is contraindicated in patients with acute systemic infection, patients with mesenteric blood flow mainly supplied by the inferior mesenteric artery, patients who have an allergic reaction to the device, patients who are not suitable for endovascular repair in vascular morphology, patients who cannot tolerate contrast agents because of renal insufficiency, and patients who are allergic to contrast agents. It is also contraindicated by aneurysm neck with thrombus, nonaneurysmal aortic proximal neck length <1.5 cm, nonaneurysmal aortic distal anchorage zone <1.5 cm, and nonaneurysmal aortic diameter <18 mm or >42 mm. Selection of patients. The safety and effectiveness of the Ankura Thoracic Stent Graft have not yet been evaluated in the following populations: patients with traumatic aortic injury; patients with uncorrectable coagulopathy; patients with hereditary connective tissue disease (eg, Marfan and Ehlers-Danlos syndromes); patients with active systemic infections; pregnant or nursing women; morbidly obese patients; patients younger than 18 years; and patients with life expectancy <1 year. Access vessel diameter (measured inner wall to inner wall) and morphology (minimal tortuosity, occlusive disease, and calcification) should be compatible with vascular access techniques and the profile of the delivery system. Vasculature that is too tortuous may increase the failure of stent graft deployment or proximal end release. The Ankura Thoracic Stent Graft is also not recommended in patients who weigh >350 pounds (150 kg) or cannot undergo accurate fluoroscopy examination because of obesity. Patients with a systemic infection may be at increased risk of endovascular stent graft infection. Furthermore, patients with uncorrectable coagulopathy may have an increased risk of type II endoleak or bleeding complications.
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Endovascular technique. Chest and abdominal CT angiography was performed in every patient before the endovascular procedure. All post-CT angiography images were transferred to a dedicated software workstation to obtain preoperative measurements. A multidisciplinary team, including cardiac and vascular surgeons and interventional radiologists, discussed and planned each case on an individual basis. All TEVAR interventions were performed in the angiography suite, equipped with an Innova angiographic system (GE Healthcare, Wauwatosa, Wisc). The angiography suite is also equipped with a complete anesthesia system with the potential for real-time full monitoring of the patient. Each patient was placed in the supine position. Both groins and the right or left arm in case the preoperative plan indicated potential use of the brachial artery were prepared and draped. Local anesthesia along with light sedation (general or regional anesthesia) was used. Spinal drainage before TEVAR was not routinely used; however, lumbar drainage was readily available in the angiography suite, and an experienced neurosurgeon was available in cases of previous aortic surgery when coverage of the subclavian artery was planned or when extensive coverage (ie, more than two-thirds) of the DTA by the stent graft was required. Our spinal cord protection protocol included maintaining an adequate mean systemic pressure during the procedure and during the recovery period and close neurologic monitoring for 48 hours after the procedure. In case of need for spinal drainage in symptomatic patients, spinal pressures <10 mm Hg were maintained for 48 hours, after which spinal catheters were removed. A broadspectrum antibiotic was administered, a femoral artery cutdown was performed on the device access site, and the patient received 5000 units of heparin. After the initial advancement of a vertebral 5F angiocatheter in the ascending aorta, a curved, extrastiff wire (Lunderquist; Cook Medical, Bloomington, Ind) was placed in the ascending aorta through this catheter. The contralateral femoral artery or the left (usually) brachial artery was punctured, and a pigtail catheter was placed under fluoroscopic guidance in the ascending aorta through a 5F sheath to perform aortography. The stent graft was prepared and advanced into the correct position on the basis of the previously obtained angiogram in the left anterior oblique projection (usually 40-45 degrees) for arch vessels and lesion mapping. The endograft comes with a delivery system with outer diameter of 18F to 24F. The endografts used in our case were mainly mounted in 21F to 24F delivery systems. Oversizing by 15% to 20% was used, according to the preoperative plan. Confirmatory aortography was performed and slight adjustments were made. Blood pressure was brought down to approximately 100 mm Hg, the device was deployed (Supplementary Fig 1, online only), and then a remodeling balloon was used (if necessary) under
fluoroscopy. Although the endograft’s IFU do not impose the routine use of endograft ballooning, a molding balloon was used selectively in cases of multiple stent grafts at the seal zones and at any overlap zones to ensure full apposition to the aortic wall when needed. The left subclavian artery was intentionally occluded in some cases to extend the proximal landing zone. In these cases, angiography was initially performed to verify the position and the patency of the left vertebral artery. Coverage of the subclavian artery without revascularization is generally well tolerated, and our team has decided to proceed without routine carotid-subclavian bypass unless the patient had prior internal mammary artery grafting. All patients were assessed for arm claudication or fatigue on follow up. After the endograft’s deployment, final angiography was then performed to assess potential endoleak. Femoral artery cutdown was sutured with 6-0 Prolene, and the wound incision was closed. After TEVAR, the patients remained in the main cardiovascular ward. All patients were discharged under single antiplatelet therapy unless contraindicated. Follow-up CT scan was performed after 1 month and 6 months and yearly thereafter. Statistical analyses. Continuous variables (Supplementary Methods, online only) were expressed as mean 6 standard deviation or median (range). Categorical variables (Supplementary Methods, online only) were expressed as proportions (percentage). All outcome rates were appropriately calculated as the ratio of events within the designated population of respective cases. Kaplan-Meier analysis was performed to obtain estimates and 95% confidence intervals of freedom from reintervention. Stata statistical software (version 12.0; StataCorp LP, College Station, Tex) was used for the analysis.
RESULTS Cohort of patients. A total of 30 nonconsecutive patients (80% male; mean age, 73.7 6 6.33 years) with DTA aneurysms were treated with Ankura Thoracic Stent Graft during the study period in our department. Baseline atherosclerotic characteristics of the cohort are shown in Table I. Among them, hypertension (57%), smoking habit (70%), and hyperlipidemia (50%) were highly prevalent. Half of our study cohort patients were treated on an elective basis; seven patients (23%) presented with rupture (Table II). One patient (3%) had a history of prior endovascular aneurysm repair. Procedure-related characteristics. Local anesthesia with light sedation was used in most of the treated patients (n ¼ 29; 97%); only one patient required general anesthesia (3%) because of the requirement for a surgical conduit (Table II). Mean duration of the TEVAR procedure was 114.5 6 38.4 minutes; dose-area product was 313.1 6 228.3 dGy cm2, and we used fluoroscopy for
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Table I. Baseline characteristics of the patients (N ¼ 30) Age, years, mean (SD)
73.7 (6.3)
Male sex
24 (80)
Hypertension
17 (57)
Diabetes mellitus
5 (17)
Hyperlipidemia
15 (50)
Smoking (present or past)
21 (70)
Coronary artery disease
8 (27)
Previous myocardial infarction
4 (13)
Arrhythmias
5 (17)
Peripheral artery disease
7 (23)
Chronic renal failure
4 (13)
Previous neurologic event
2 (7)
Chronic obstructive pulmonary disease
7 (23)
SD, Standard deviation. Values are reported as number (%) unless otherwise indicated.
Table II. Operation-related characteristics (N ¼ 30) Clinical symptoms Elective repair
15 (50)
Symptomatic DTA aneurysm
8 (27)
Ruptured DTA aneurysm
7 (23)
Type of prior aortic treatment None
29 (97)
EVAR
1 (3)
Type of anesthesia used Local
29 (97)
General
1 (3)
Technical success
29 (97)
Duration of operation, minutes Fluoroscopy time, minutes Dose-area product, dGy cm
114.5 (38.4) 12.9 (6.2)
2
313.1 (228.3)
Contrast material administered, mL
202.3 (55.4)
Blood loss, mL
272.3 (149.4)
Length of hospital stay, days
4.3 (2.9)
DTA, Descending thoracic aorta; EVAR, endovascular aneurysm repair. Categorical variables are presented as number (%). Continuous variables are presented as mean (standard deviation).
12.9 6 6.2 minutes. The mean contrast material volume administered was 202.3 6 55.4 mL, whereas blood loss was estimated at 272.3 6 149.4 mL. Only one patient (3%) needed transfusion at the end of the procedure because of a low preoperative hemoglobin level. All patients were discharged after a mean of 4.3 6 2.9 days. DTA characteristics and technical details of the procedure. Technical success of the procedure was 97% (29/ 30 patients). One patient required a surgical conduit in the common iliac artery because of small diameter and heavily calcified femoral arteries. The sole patient with technical failure had a successful initial delivery of the
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endograft into the correct aortic position, but the deployment was unsuccessful, probably because of the extreme tortuosity of the DTA (Supplementary Fig 2, online only). The device was kinked and we could not unsheathe the endograft. The whole device was thereafter retrieved from the aorta. In this same patient, a second device of a different commercial type was used, which also failed to overcome the kinked aorta, and finally the case was abandoned. As shown in Table III, among the 29 patients with successful endograft implantation, the maximum diameter of the DTA was 73 6 1.5 mm. Proximal landing zone of the stent graft was zone 2 in 3 cases (10%), with a mean diameter of 33 6 3.5 mm, and zone 3 in the remaining 26 patients (90%), with a mean diameter of 34 6 4.4 mm. Distally, endografts were landed in zone 4 and 5 in 28 patients (97%; mean diameter, 34 6 3.5 mm and 32 6 3.5 mm, respectively) and in zone 6 in one patient (3%; diameter, 32 mm). We used the common femoral artery as the main access vessel in 28 patients (97%), whereas 1 patient required a surgical conduit, as reported previously. A total of 15 patients (52%) required only one stent graft; in 11 patients (38%), a second stent graft was necessary; and in 3 patients (10%), three stent grafts were used for appropriate sealing. We covered the left subclavian artery without any additional procedure in three patients (10%) because of insufficient proximal landing zone, with no postoperative complication. Early (30-day/in-hospital) follow-up. During the early follow-up, two (7%) access site complications were recorded, mainly small hematoma and serous collection, which did not require any operation (Table IV). Apart from one patient (3%) who developed a postoperative pulmonary infection, no other major adverse event, including cerebral, cardiac, or renal complication requiring dialysis, was observed. A total of two patients (7%) developed early postoperative paralysis or paraparesis, which immediately resolved after lumbar drainage. One patient (3%) died while in the hospital of gastrointestinal bleeding; another patient died during the first 30 days after the procedure of sepsis after pulmonary infection. Late (post-30-day/in-hospital) follow-up. A 10% (n ¼ 3) type I endoleak rate was recorded during follow-up. More specifically, two patients (7%) developed type IA (proximal) and one patient (3%) developed type IB (distal) endoleak. The patient with type IB endoleak was reoperated on after the first follow-up CT scan (1 month), and coverage of the celiac trunk with a stent graft was required because of short distal landing zone. Since then and during follow-up, the patient has not developed any kind of endoleak; the branches of the celiac trunk are supplied through the superior mesenteric artery collaterals. Of the two patients with type IA endoleak, one was
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Table III. Aorta-related and technical characteristics among patients with successful endograft implantation (N ¼ 29)
Table IV. Outcomes among patients with successful endograft implantation during follow-up, including 30-day/in-hospital outcomes (N ¼ 29)
Maximum diameter of DTA, mm
Variables
73 (1.5)
Proximal diameter of DTA, mm
Access site complications
Zone 2
33 (3.5)
Endoleak
Zone 3
34 (4.4)
Type I
Distal diameter of DTA, mm
Type II
No. (%) 2 (7) 3 (10) 1 (3)
Zone 4
34 (3.5)
Cerebral complications
1 (3)
Zone 5
32 (3.6)
Cardiac complications
0 (0)
Paralysis or paraparesis
2 (7)
Proximal landing zone Zone 2
3 (10)
Zone 3
26 (90)
Distal landing zone Zone 4-5 Zone 6
28 (97) 1 (3)
Access site Femoral Other
28 (97) 1 (3)
Pulmonary complications
1 (3)
Renal failure requiring dialysis
0 (0)
Retroaortic type A dissection
0 (0)
In-hospital mortality
1 (3)
Aorta-related mortality
0 (0)
30-Day mortality
2 (7)
Reinterventions
3 (10)
Mortality at end of follow-up
4 (14)
No. of stent grafts used 1
15 (52)
2
11 (38)
3 Coverage of left subclavian artery
3 (10) 3 (10)
DTA, Descending thoracic aorta. Categorical variables are presented as number (%). Continuous variables are presented as mean (standard deviation).
successfully reoperated on with a new, proximally implanted endoprosthesis. The second patient refused any reoperation; however, his CT scan images at 6 months and 1 year of follow-up showed partial thrombosis of the aneurysm sac with no increase in its diameter (5.5 cm since the beginning). One patient (3%) was diagnosed with type II endoleak at the 6-month follow-up CT examination, and he was treated with implantation of a vascular plug at the orifice of the left subclavian artery. As a result, the reintervention rate in our cohort was 10% (3/29). Kaplan-Meier analysis with estimates and 95% confidence intervals of freedom from reintervention are provided in the Fig. No aorta-related death was observed. One patient died 2 months after operation of H1N1 influenza acute respiratory distress syndrome. During a median follow-up of 31.7 (range, 38.4) months, two more patients died of non-TEVAR-related causes, one of stroke from carotid artery disease, in whom the left subclavian artery was not covered, and the other of motor vehicle trauma. In the rest of the cohort, no other adverse events were recorded.
DISCUSSION This cohort consisted of 30 patients with thoracic aortic aneurysms treated with the Ankura Thoracic Stent Graft. Technical success was high at 97%, with only one failure
Fig. Kaplan-Meier analysis with estimates and 95% confidence intervals (CIs) of freedom from reintervention.
outside of IFU due to high tortuosity of the DTA in a patient at high risk for open surgery. Safety and efficacy of the endograft were documented as we did not record any serious major adverse events; the two cases of spinal cord ischemia were immediately resolved with lumbar drainage, leaving no permanent effect. A 7% rate of proximal endoleak was recorded in symptomatic patients with short proximal neck; however, apart from one patient who refused further treatment, all endoleaks were successfully sealed with simple early endovascular reinterventions. Endovascular repair of DTA has been proved to be relatively safe and has been demonstrated to be effective in preventing aortic rupture. Our study showed satisfactory
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early outcomes, comparable to outcomes reported by large studies of already established thoracic endografts. Among these studies, the GORE TAG (W. L. Gore & Associates, Flagstaff, Ariz) endoprosthesis was the first DTA device to enter phase 2 trials in the United States. In a cohort of 139 patients, the device was successfully implanted in 98% of the patients. Early 30-day results demonstrated a 1.5% mortality rate, 4% stroke rate, and 3% temporary or permanent paraplegia and 9% bleeding complications. During a 24-month follow-up, 2.9% aneurysm-related mortality was recorded, whereas no aortic ruptures occurred. Interestingly, the authors reported 20 wire fractures in 19 patients, of which only 1 required treatment.6 At 5 years, aneurysm-related mortality for TAG patients was 2.8%. Endoleaks decreased from 8.1% at 1 month to 4.3% at 5 years, whereas major aneurysm-related reinterventions at 5 years were 3.6%.7 During the 5-year follow-up of the TAG endograft, there have been no ruptures, one migration, and no collapse; after revision of the endograft into the modified lowporosity device at 24 months, sac increase was detected in 12.9% of the original vs 2.9% of the modified grafts.7 In another study, Zenith TX1 and TX2 (Cook Medical, Bloomington, Ind) devices for TEVAR proved to have durable outcomes, with aneurysm-related survival being 91.7% at 5 years.8 Freedom from any endoleak was 77.8%, 77.2%, 72.2%, and 62.3% at 1 year, 2 years, 5 years, and 9 years, respectively. Zenith TX2 was also evaluated by another study,9 showing endoleak in 3.9% and migration in 2.8% at 12 months. None of the patients had stent fracture, barb separation, stent to graft separation, or component separation. The authors reported 2.5% stroke, 1.3% paraplegia, and 4.4% paraparesis rate occurring before the first 30 days after TEVAR.9 Moreover, Zenith Alpha (Cook Medical) endograft also evidenced great results in a study of 70 TEVAR patients.10 During the <2-year mean follow-up, the authors reported no conversions to open repair and no ruptures or intraoperative deaths. A 4.3% and 2.9% rate of type IA and type IB endoleak, respectively, with no type III or type IV endoleak was recorded. There was one case of distal stent graft migration and no stent fracture; reintervention was necessary in only 1.4% of the study cohort. The Evaluation of the Medtronic Vascular Talent Thoracic Stent Graft System for the Treatment of Thoracic Aortic Aneurysms (VALOR) trial also enrolled 195 TEVAR patients. Freedom from aneurysm-related mortality was 96.9% at 1 year and 96.1% at 5 years; endoleak type I and type III occurred in 4.6% and 1.3% of the study population at 1 month, respectively. Through the 5-year follow-up, 14.4% of the patients underwent additional endovascular procedures on the original target lesion. Stent graft migration was noted in 0.6% in the first year.11 The VALOR II trial enrolled 160 patients with higher rates of cardiovascular risk factors and significantly more severe modified Society for Vascular Surgery/American
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Association for Vascular Surgery risk scores compared with the VALOR trial. Outcomes at 30 days were 3.1% perioperative mortality, 0.6% paraplegia, 1.9% paraparesis, and 2.5% stroke.12 In the Bolton Relay Thoracic Aortic Endovascular Pivotal Trial,13 which enrolled 120 patients, thoracic endografts were delivered and deployed in 97.0% of the study sample. The authors reported a 30-day mortality rate of 5.3%. At 5 years, freedom from aneurysmrelated mortality was 91.3%. Type I or type III endoleak was 4.5%, whereas in 7.5% of the patients, secondary procedures were required to correct the endoleak. The study detected a 2.3% endograft migration rate, with 1.5% wire form fracture rate. Modifications to the original delivery system led to improved outcomes with uniform technical success, no instances of endoleak and migration or fracture, and a significant decrease in strokes (2.6% vs 12.6% with the original endograft).13 Finally, putting evidence together, a recent meta-analysis14 collected data from 11 studies reporting on 673 patients treated with TEVAR for DTA aneurysm. Technical success was 91.0% of patients, with pooled overall 30-day and 3-year survival rates at 96.0% and 74.0%, respectively. Paraplegia occurred in 3.2% of patients and was permanent in 1.4% of patients, whereas the stroke rate was 2.7%. The authors reported 7.3% early type I endoleak, with type II endoleak in 2.0% and type III in 1.2% of the patients. Freedom from reintervention was 90.3% at the end of follow-up.14 The most important strength of our study is the firstever reported results of a new thoracic endograft with strict inclusion criteria concerning the aortic disease. However, our study has some limitations that should also be addressed. First, the number of study participants is lower compared with the already published big series for other endografts, thus making direct comparison of results difficult. Furthermore, the selection of patients was made on an individual patient basis, and as result, this might have introduced a potential selection bias. Moreover, although this is a retrospective review of prospectively collected data, it lacks a control group composed of TEVAR patients treated with other commercially available endografts or open repair patients, which would be ideal in terms of comparing the results. What is more, this series represents a “reallife” single-center experience, and therefore results should be confirmed by future high-volume multicenter, prospective studies. Last, our follow-up period is not long enough, making long-term durability of the endograft unexplored.
CONCLUSIONS The Ankura Thoracic Stent Graft seems to provide a safe, effective, and durable endoprosthesis for the treatment of atherosclerotic thoracic aortic aneurysms. It showed a 0% aneurysm-related mortality during
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follow-up and low endoleak and overall complication rate. However, the long-term durability of the endograft should be tested after a longer follow-up period.
AUTHOR CONTRIBUTIONS Conception and design: TK, CA, DT, PD, VP, IS, JK, DF, MA Analysis and interpretation: TK, CA, DT, MA Data collection: TK, DT Writing the article: TK, CA Critical revision of the article: TK, CA, DT, PD, VP, IS, JK, DF, MA Final approval of the article: TK, CA, DT, PD, VP, IS, JK, DF, MA Statistical analysis: CA Obtained funding: Not applicable Overall responsibility: CA TK and CA contributed equally to this article and share co-first authorship.
REFERENCES 1. Bonser RS, Pagano D, Lewis ME, Rooney SJ, Guest P, Davies P, et al. Clinical and patho-anatomical factors affecting expansion of thoracic aortic aneurysms. Heart 2000;84:277-83. 2. Fowkes FG, Macintyre CC, Ruckley CV. Increasing incidence of aortic aneurysms in England and Wales. BMJ 1989;298: 33-5. 3. Johansson G, Swedenborg J. Ruptured abdominal aortic aneurysms: a study of incidence and mortality. Br J Surg 1986;73:101-3. 4. Jonker FH, Verhagen HJ, Lin PH, Heijmen RH, Trimarchi S, Lee WA, et al. Open surgery versus endovascular repair of ruptured thoracic aortic aneurysms. J Vasc Surg 2011;53: 1210-6. 5. Perko MJ, Norgaard M, Herzog TM, Olsen PS, Schroeder TV, Pettersson G. Unoperated aortic aneurysm: a survey of 170 patients. Ann Thorac Surg 1995;59:1204-9.
6. Makaroun MS, Dillavou ED, Kee ST, Sicard G, Chaikof E, Bavaria J, et al. Endovascular treatment of thoracic aortic aneurysms: results of the phase II multicenter trial of the GORE TAG thoracic endoprosthesis. J Vasc Surg 2005;41:1-9. 7. Makaroun MS, Dillavou ED, Wheatley GH, Cambria RP; Gore TAG Investigators. Five-year results of endovascular treatment with the Gore TAG device compared with open repair of thoracic aortic aneurysms. J Vasc Surg 2008;47:912-8. 8. Beach JM, Kuramochi Y, Brier C, Roselli EE, Eagleton MJ. Durable outcomes of thoracic endovascular aortic repair with Zenith TX1 and TX2 devices. J Vasc Surg 2017;65:1287-96. 9. Matsumura JS, Cambria RP, Dake MD, Moore RD, Svensson LG, Snyder S, et al. International controlled clinical trial of thoracic endovascular aneurysm repair with the Zenith TX2 endovascular graft: 1-year results. J Vasc Surg 2008;47:247-57; discussion: 257. 10. Torsello GF, Inchingolo M, Austermann M, Torsello GB, Panuccio G, Bisdas T. Durability of a low-profile stent graft for thoracic endovascular aneurysm repair. J Vasc Surg 2017;66:1638-43. 11. Foley PJ, Criado FJ, Farber MA, Kwolek CJ, Mehta M, White RA, et al. Results with the Talent thoracic stent graft in the VALOR trial. J Vasc Surg 2012;56:1214-21.e1. 12. Fairman RM, Tuchek JM, Lee WA, Kasirajan K, White R, Mehta M, et al. Pivotal results for the Medtronic Valiant Thoracic Stent Graft System in the VALOR II trial. J Vasc Surg 2012;56:1222-31.e1. 13. Farber MA, Lee WA, Szeto WY, Panneton JM, Kwolek CJ. Initial and midterm results of the Bolton Relay Thoracic Aortic Endovascular Pivotal Trial. J Vasc Surg 2017;65: 1556-66.e1. 14. Biancari F, Mariscalco G, Mariani S, Saari P, Satta J, Juvonen T. Endovascular treatment of degenerative aneurysms involving only the descending thoracic aorta: systematic review and meta-analysis. J Endovasc Ther 2016;23:387-92.
Submitted Mar 31, 2018; accepted Jul 26, 2018.
Additional material for this article may be found online at www.jvascsurg.org.
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SUPPLEMENTARY METHODS (online only). Variables of interest extracted from patients’ medical records. Preoperative factors extracted from the patients’ medical records included age, sex, atherosclerotic comorbidities (hypertension, diabetes mellitus, hypercholesterolemia, history of smoking, coronary artery disease, previous myocardial infarction, any arrhythmias, peripheral artery disease, chronic renal failure, previous neurologic event, chronic obstructive pulmonary disease), and any connective tissue disorder. Operationrelated characteristics included clinical symptoms, type of prior aortic treatment, type of anesthesia used, duration of operation, fluoroscopy time, dose-area product, volume of contrast material administered, volume of blood loss, and length of hospital stay. We also extracted aorta-related characteristics, including the proximal, distal, and maximum diameter of the descending thoracic aorta (DTA), the access site, the number of stent grafts used, the percentage of patients who needed coverage of the left subclavian artery, and the type of concomitant procedure when needed. We defined technical success as the successful and accurate deployment of the stent graft after any additional intraoperative procedure when necessary. We collected data about the 30-day and follow-up outcomes, including presence of access site complication, endoleak of any type, neurologic event, myocardial infarction, paralysis or paraparesis, pulmonary complication, renal failure, retroaortic type A dissection, and any reintervention. We estimated the 30-day and in-hospital mortality as well as aorta-related mortality, and we also recorded follow-up. The Ankura Thoracic Stent Graft (Lifetech, Shenzhen, China) is a self-expanding straight or tapered endoprosthesis made of an expanded polytetrafluoroethylene (ePTFE) dual membrane that contains sinusoidal selfexpanding nitinol springs. There is no suture on the main body to avoid pinhole leakage and thus to provide better biocompatibility and durability. The sinusoidal shape and placement of the self-expanding nitinol springs also provide flexibility and conformability in the stent graft, exerting radial force to enhance seal and fixation. The stent graft is premounted into a low-profile (21F-24F) delivery system with hydrophilic coating that is kink resistant to facilitate the delivery in tortuous and atherosclerotic arteries. Interestingly, after graft deployment and before tip capture release, it is still possible to make small final positional adjustments because of the nitinol scaffolding, which is internal to the double ePTFE membrane. The first nitinol spring strut has shorter length compared with the rest of the nitinol springs. This provides optimal fixation with enhanced apposition to the aortic wall and efficient conformability, especially in angulated necks, decreasing the possibility of endoleak and preventing the risk of migration. The proximal part
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of the stent graft is provided with a fixation system of six bare stents that distribute the radial force over multiple apices. This allows the deployment over the left subclavian artery or even the left common carotid artery without occluding the blood flow, thus providing an extended proximal landing zone. Another unique characteristic is that the proximal bare stents are embedded in the stent graft to be less traumatic, providing a clear advantage in case of traumatized aortic wall, such as in dissections. The proximal barbs remain covered by the clasping system until complete deployment, whereas the distal part of the graft has a closed web configuration. The stent graft is also provided with a longitudinal supporting bar on the greater curvature, which prevents shortening and provides axial support. To optimize the graft’s sealing, there is no bar in the first and last nitinol spring strut. The Ankura Thoracic Stent Graft comes with two radiopaque markers in its proximal covered part. The first is a “figure 8”-shaped marker placed at the greater curvature, and the second is a “figure 0”-shaped marker at the lesser curvature. Both provide high visibility and assist in accurate graft orientation and deployment. The deployment process is easy and specially designed to be operator friendly as the delivery system is provided with a two-handle system; the front handle must be kept fixed with the operator’s left hand while the second handle is being rotated clockwise by the operator’s right hand, allowing a slow and controlled deployment of the graft. However, a fast deployment is also possible by pulling back a safety valve on the second handle. The operator is releasing the clasping system of the stent graft in two movements: first, by removing the safe buckle (green), then by pulling back the tip releaser (black). Finally, to keep the correct orientation during the advancement of the stent graft in the DTA, there is a side port at the delivery system of the endoprosthesis that must be oriented at the 3-o’clock position to keep the longitudinal bar toward the external curvature of the DTA. However, in some cases, because of the aorta’s tortuosity, small adjustments may be needed in the graft’s orientation; in this situation, the operator has to keep the figure 8 proximal marker at the external curvature of the DTA and the figure 0 marker at the aorta’s lesser curvature. Technical comparison of commercially available endografts. Lifetech Ankura Thoracic Stent Graft has the advantage of no suture on the main body, thus avoiding pinhole leakage, which may cause type IV endoleak, and it is preloaded in a kink-resistant delivery system with hydrophilic coating. Furthermore, it is specially designed, allowing precise localization, which is especially crucial in case of lack of proximal landing zone. Its flexibility is excellent because of the unique design of the “sandwich”-like structure, and the longitudinal supporting
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strut on the greater curvature avoids stent shortening and provides axial support. Among the various commercially available endografts, the TAG (W. L. Gore & Associates, Flagstaff, Ariz) endoprosthesis is a flexible nitinol-supported PTFE graft in which the exoskeleton is bonded to the graft material without sutures. The release of the constraining sleeve allows rapid deployment of the endograft and expansion from the middle of the endoprosthesis toward the ends of the graft, thus avoiding displacing forces of the high arterial flow when the device is partially deployed. The Zenith TX2 (Cook Medical, Bloomington, Ind) endovascular graft is a one- or two-piece tubular endoprosthesis constructed of full-thickness woven polyester fabric sewn to self-expanding stainless steel. Stability and the expansile force are achieved by the fully stented endograft; sealing is secured by the barbs at the distal and proximal ends. Contrary to the TAG endoprosthesis, the Zenith TX2 endograft is provided with a delivery system that allows staged and controlled placement in the often tortuous thoracic aorta.1 The newer generation Zenith Alpha (Cook Medical) thoracic stent graft features a tightly woven polyester graft, sewn to self-expanding nitinol stents with monofilament polypropylene sutures, that allows loading of the graft in low-profile delivery systems ranging between 16F and 20F.2 The Valiant (Medtronic, Santa Rosa, Calif) stent graft system is a modular, self-expanding, tubular endoprosthesis composed of a series of serpentine five-peaked springs stacked in a tubular configuration and compressed and preloaded in a single-use disposable catheter with an integrated handle. The endograft has eight-peak configuration in its proximal bare spring, intended to distribute the radial force across more points of contact, resulting in less force per point.3 Another commercially available endograft, the Relay (Bolton Medical, Sunrise, Fla) thoracic stent graft, is a modular device composed of self-expanding nitinol stents sutured to polyester fabric with a bare proximal stent and covered distal stent, and there is also a curved nitinol wire that provides longitudinal support. The unique characteristic of the endograft is that the connecting bars are not attached to the proximal sealing stent configuration. The endoprosthesis has a two-stage device deployment technique that facilitates navigation and alignment.4
Technical tips and overall operator’s impression of Lifetech Ankura endograft. d The device needs to be watered first from the back part of the delivery system and then from the lateral side port, and similar to other devices, the operator has to put in some force to bring out all possible air bubbles from the delivery system. d After this step, plenty of saline water needs to be spread over the hydrophilic part of the delivery system, and we suggest waiting a few seconds before use of the device to get the maximum hydrophilic effect. d There is no gap between the tip of the delivery system and the hydrophilic part of the delivery system, which permits the smooth advancement of the device through the femoral and iliac arteries if adequate artery diameter exists. d The delivery system is kink resistant and usually succeeds in overpassing even extreme aortic tortuosity. The graft is highly visible during fluoroscopy, and both proximal radiopaque markers (figure 0 and figure 8) are easily depicted. d The feeling during the graft’s deployment is of an accurate positioning graft, and we propose deployment of the first two nitinol springs, then proceeding with fast graft withdrawal. d As this is an e-PTFE graft, we advise avoiding the use of a remodeling balloon as in a few cases we noticed small graft migration after ballooning. d After graft deployment, resheathing of the tip was always uneventful, and even in very tortuous aortas, we managed to retrieve it by rotating the delivery system.
SUPPLEMENTARY REFERENCES 1. Matsumura JS, Cambria RP, Dake MD, Moore RD, Svensson LG, Snyder S, et al. International controlled clinical trial of thoracic endovascular aneurysm repair with the Zenith TX2 endovascular graft: 1-year results. J Vasc Surg 2008;47: 247-57; discussion: 257. 2. Torsello GF, Inchingolo M, Austermann M, Torsello GB, Panuccio G, Bisdas T. Durability of a low-profile stent graft for thoracic endovascular aneurysm repair. J Vasc Surg 2017;66: 1638-43. 3. Fairman RM, Tuchek JM, Lee WA, Kasirajan K, White R, Mehta M, et al. Pivotal results for the Medtronic Valiant Thoracic Stent Graft System in the VALOR II trial. J Vasc Surg 2012;56:1222-31.e1. 4. Farber MA, Lee WA, Szeto WY, Panneton JM, Kwolek CJ. Initial and midterm results of the Bolton Relay Thoracic Aortic Endovascular Pivotal Trial. J Vasc Surg 2017;65:1556-66.e1.
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Supplementary Fig 1 (online only). Device characteristics of Lifetech Ankura Thoracic Stent Graft.
Supplementary Fig 2 (online only). Digital subtraction angiography showing a case of tortuous aorta.
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