- Email: [email protected]
Mid- to Long-Term Outcome Results of the Ovation Stent Graft
Clinical Research Mid- to Long-Term Outcome Results of the Ovation Stent Graft Hozan Mufty,1 Sabrina Houthoofd,1 Kim Daenens,1 Inge Fourneau,1 and Geert Maleux,2 Leuven, Belgium
Background: To report mid-term to long-term outcome data for endovascular aortic repair using the Ovation stent-graft system (Endologix, Santa Rosa, CA) in a single university center. Methods: All patients treated with the Ovation stent graft between February 2012 and January 2019 were included. Patient demographics, anatomical and operative details, as well as followup data including complications, need for further interventions, and mortality were analyzed. Results: A total of 74 patients (93% males; mean age, 74.5 years) were treated with the Ovation stent graft. The median maximal aortic diameter was 60 mm (range, 36e100). Sixtytwo of 74 patients (83.8%) were considered to have a hostile neck. About 33% had a (reversed) conical neck, 59% had circumferential neck calcification (>50%), and 39% had significant neck thrombus (>50%). Technical success rate was 91.89%. Despite additional measures, 4 patients had a persistent type Ia endoleak on completion angiography, of which 3 disappeared on the first postoperative computed tomography angiography. Mean follow-up duration was 31.62 months ± 21.3 (range, 0e72.74 months). Twenty-four patients had a follow-up time of at least 36 months. Freedom from reintervention at 1, 2, 3, and 5 years was 92.7%, 90.8%, 80.1%, and 80.1%, respectively. Estimated freedom from mortality at 1, 2, 3, and 5 years was 96.8%, 95.0%, 87.3%, and 68.5%, respectively. No late type Ia or type III endoleak was detected during follow-up. No aneurysm-related mortality was seen. Conclusions: Our mid- to long-term experience with the Ovation stent-graft system demonstrates safe and durable results without late type Ia or type III endoleak.
INTRODUCTION The Ovation stent-graft system (Endologix, Santa Rosa, CA) is an endoprosthesis with a trimodular Conflicts of interest: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The hospital receives consultancy fees for Ovation workshops. Ethical approval: Ethical approval was obtained by the local ethics committee of the hospital (S62135). 1 Department of Vascular Surgery, University Hospitals Leuven, Leuven, Belgium. 2 Department of Radiology, University Hospitals Leuven, Leuven, Belgium.
Correspondence to: Hozan Mufty, MD, Department of Vascular Surgery, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium; E-mail: [email protected] @UZLeuven Ann Vasc Surg 2019; -: 1–7 https://doi.org/10.1016/j.avsg.2019.06.045 Ó 2019 Elsevier Inc. All rights reserved. Manuscript received: May 7, 2019; manuscript accepted: June 28, 2019; published online: - - -
design for the treatment of infrarenal aortic aneurysms. The suprarenal nitinol stent with integrated anchors for fixation in combination with inflatable polymer-filled sealing rings has already proven to extend the on-label eligibility criteria for endovascular aortic repair (EVAR).1,2 In contrast to stentsupported endograft sealing, these sealing rings are not associated with aortic neck dilation.3 The low profile 14F delivery system allows treatment of abdominal aortic aneurysms with small or narrowed in-diameter access vessels. Since the introduction of the Ovation stent-graft system, delivery system enhancements (ultra-low profile design, integrated sheath) are introduced. Ovation, Ovation Prime, and finally Ovation iX with the built-in procedural option to facilitate contralateral limb placement have already proven to have a safe outcome with very satisfactory early and mid-term results.1,4 Until now, long-term outcome results and comparative 1
2 Mufty et al.
studies are lacking.1,4e6 In this retrospective study, we present our single-center mid-term to longterm outcome results with the use of the Ovation, Ovation Prime, and Ovation iX stent-graft system during 6 years.
MATERIALS AND METHODS All patients treated with the Endologix Ovation platform (including Ovation, Ovation Prime, and Ovation iX Abdominal stent-graft system) between February 2012 and January 2019 in a single center university hospital were retrospectively analyzed from a prospective database. All patients gave informed consent before the EVAR procedure, both for the procedure and the follow-up scheme as defined by the Belgian National Health insurance Office. No ruptured cases were treated with this stent-graft system. In our center, open surgery is recommended for minimal risk young patients and medium-risk to high-risk patients with unsuitable anatomy for standard or complex fenestrated or branched EVAR. In our center, different stent-graft types are used. Challenging necks are preferably treated with the Ovation stent graft. Patients within both inside and outside the instructions for use (IFU) were included. Criteria for treatment were an aortic diameter 55 mm in men or 50 mm in women and fast growth (>5 mm in 6 months). Patients were considered to have a hostile aortic neck anatomy if: infrarenal neck angulation was 60, neck length <10 mm, infrarenal aortic diameter <16 mm or >30 mm, and unfavorable neck shape, such as conical, reversed conical, >50% calcification, and circular or semicircular thrombus. Preoperative imaging was performed by computed tomography angiography (CTa). In case of severe renal insufficiency magnetic resonance angiography in combination with unenhanced CT to display calcified plaques was performed. In these cases, procedures were performed with the use of carbon dioxide angiography. Procedures were performed in a hybrid operating room with a fixed c-arm system (Artis Zeego; Siemens AG, Forchheim, Germany). Under local or general anesthesia, femoral access was performed both through surgical cutdown and/or by an endovascular approach with the use of a closure device. Technical success was defined as successful deployment of the stent graft without type I or III endoleak, successful removal of the delivery system, and no unintentional coverage of visceral aortic branches or hypogastric arteries. Our follow-up protocol consisted of a clinical checkup 4 weeks postoperatively and a CTa after 3
Annals of Vascular Surgery
Table I. Patient demographics Characteristics
n (%)
Male/female Hypercholesterolemia Arterial hypertension BMI Smoking Never Active Ceased Peripheral arterial disease Coronary artery disease Chronic kidney disease (eGFR <60 mL/min) Cerebrovascular disease Diabetes No Insulin dependent Noninsulin dependent ASA classification I II III IV Medication Antiaggregant Anticoagulant
69 (93)/5 (7) 65 (88) 57 (77) 27.85 ± 4.0 17 16 41 16 35 20
(23) (22) (55) (22) (47) (27)
7 (9) 60 (81) 2 (3) 12 (16) 1 11 54 8
(1) (15) (73) (11)
58 (79) 7 (10)
BMI, body mass index; eGFR, estimated glomerular filtration rate; ASA, American Society of Anesthesiologists.
months and 1 year. In accordance to the EUROpean collaborators on Stent-graft Techniques for abdominal aortic Aneurysm Repair criteria,7 if no endoleak was seen and the aortic diameter remained stable or decreased, further follow-up was performed by annual duplex ultrasound (DUS) and abdominal X-ray. Patients with persistent signs of endoleak were further followed by CTa. Stent graft migration, endoleaks, reinterventions, and time and cause of death were recorded. SPSS for Windows (version 25; SPSS Inc, Chicago, IL) was used for statistical analysis. Variables are presented as mean ± standard deviation in case of normal distribution and median + range in case of skewed distribution. Kaplan-Meier estimate was used to define survival and reintervention during follow-up.
RESULTS Between February 2012 and January 2019, 74 patients (mean age, 74.5 years ± 7.68) were treated with the Endologix Ovation platform for infrarenal aortic disease. Patient demographics are reported in Table I. Most patients presented with a fusiform
Volume
-, -
2019
Mid-term outcome of the Ovation stent graft 3
Table II. IFU of different stent grafts
Graft
Neck length (mm)
E-Tegra (Jotec, Hechingen, Germany) Zenith-Alpha (Cook Medical, Bloomington, IN) Gore C3 (W.L. Gore & Associates, Flagstaff, AZ) Incraft (Cardinal Health, Dublin, Ireland) Endurant II (Medtronic, Santa Rosa, CA) Ovation iX (Endologix, Santa Rosa, CA)
15 15 15 10 10 10 if aortic angle 60 <10 if aortic angle 45
Diameter Neck proximal Alfa diameter landing angle Patients outside (mm) IFU, n/N (%) zone (mm) ( )
19e32 18e32 19e32 17e31 19e32 16e30
8e25 7.5e20 8e25 7e22 8e25 8e25
75 <60 <60 60 <60
8/74 13/74 13/74 10/74 11/74 8/74
(10.8) (17.5) (17.5) (13.5) (14.8) (10.8)
Fig. 1. (A and B) An 84-year-old patient with semicircular neck thrombus on preoperative and postoperative CTa. (C) A 79-year-old patient with renal insufficiency
and significant aortic neck calcification preoperatively. (D) Postoperative CTa showing good apposition of the polymer-filled sealing ring.
infrarenal aortic aneurysm (n ¼ 70; 95%). The 4 remaining patients were treated for a saccular aneurysm of the aorta. The median maximal aortic diameter was 60 mm (range, 36e100). Patients with maximal aortic diameter <55 mm for men and
<50 for women were treated for saccular aneurysm. The number of patients treated within IFU is depicted in Table II. Angulation was the only reason to be outside IFU in our study group. Sixty-two of 74 patients (83.8%) were considered to have a hostile
4 Mufty et al.
Annals of Vascular Surgery
Table III. Aneurysm characteristics Mean neck diameter Median neck length Mean aortic neck angulation Hostile neck, n/N (%) Significant neck calcification Circular neck thrombus Semicircular neck thrombus Neck morphology Tapered Reversed tapered
23.37 mm ± 3.28 32 mm (range, 13e79) 33 ± 18.96 (range, 3e80) 62/74 (83.8) 44/74 (59) 9/74 (12) 20/74 (27) 7/74 (9) 18/74 (24)
neck (Fig. 1). Aneurysm characteristics are provided in Table III. Two of 74 patients needed preoperative coiling of a hypogastric artery to create a safe distal sealing zone. One patient had a very large caliber inferior mesenteric artery that was occluded preoperatively with an Amplatzer vascular plug (St Jude Medical, St Paul, MN). One patient with peripheral arterial disease required an iliofemoral bypass through groin incision, and 2 patients needed balloon angioplasty of the iliac artery to make delivery of the endograft possible. Technical success rate was 91.89%. One patient needed additional limb relining and stenting because of persistent kinking/stenosis. Despite additional measures such as ballooning, 4 patients had a persistent type Ia endoleak on completion angiography. In this group, 1 patient received an Excluder aortic cuff (W.L. Gore & Associates, Flagstaff, AZ) because of a low release of the stent graft. One patient had type Ib endoleak, and 1 patient had type III endoleak. The latter patient received additional kissing Advanta V12 (Atrium Maquet Getinge Group, Mijdrecht, The Netherlands) without resolution of the endoleak. Three of 4 type Ia endoleaks and type Ib endoleak disappeared spontaneously on the first postoperative CTa. In the patient with the aortic cuff, type Ia endoleak was still present on the first CTa with outflow over the inferior mesenteric artery. This could be successfully treated with Onyx and coils. Twenty-two months postoperatively, a stable aortic diameter was seen with no signs of endoleak. The patient with type III endoleak was a 55-year-old male with an aortic aneurysm of 64 mm. Because of comorbidities, an endovascular approach was preferred. On the first postoperative CTa, it became clear that the operation was complicated by inadvertent bilateral iliac limb insertion into the right gate without cannulation of the left gate. The left outflow inferior mesenteric artery was coil embolized, and the inflow left gate was closed with an Amplatzer plug.8 Follow-up CTa after 70 months
still showed the absence of any endoleak and a decrease of aortic diameter toward 60 mm. No 30day mortality occurred. Mean follow-up duration was 31.62 months ± 21.3 (range, 0e72.74). Twenty-four patients had a follow-up time of at least 36 months, 19 patients had a follow-up time of at least 48 months, and 12 patients had a follow-up time for at least 5 years. Freedom from reintervention at 1, 2, 3, and 5 years was 92.7% ± 3.1, 90.8% ± 3.6, 80.1% ± 6.0, and 80.1% ± 6.0, respectively (Fig. 1). No limb thrombosis occurred. Three patients received transarterial embolization of type II endoleak, and 2 patients underwent direct embolization of type II endoleak. One patient with extreme calcified aortoiliac disease needed additional groin endarterectomy and endovascular repair of the iliac axis because of ischemic complaints (Rutherford stage 5) after extubation. Another patient with a narrow aortic bifurcation presented 8 days postoperatively at the emergency department with claudication complaints at the left side. CTa revealed a compression of the left limb at the level of the flow divided. This was successfully treated by kissing stenting with 2 Advanta V12 stents. Finally, one 91-year-old patient presented with a symptomatic type Ib endoleak because of progression of aneurysmatic disease of the common iliac artery and concomitant stent migration 31 months postoperatively. This was treated by limb relining. No late type Ia or type III endoleak was detected during follow-up. Estimated freedom from mortality at 1, 2, 3, and 5 years was 96.8% ± 2.2, 95.0% ± 2.8, 87.3% ± 5.0, and 68.5% ± 8.5 (Fig. 2). During follow-up, 13 patients died after a mean follow-up time of 38.1 months (range, 7.3e62.6), and mean age was 79 ± 8.0 years. Five of these 13 patients died during follow-up because of an unknown cause. Nevertheless, no patients were lost to follow-up. Of these 5 patients, only 2 patients had type II endoleak in final follow-up imaging without significant (>5 mm) growth of the aneurysm. One patient died of cardiac decompensation, 1 of pulmonary embolism unrelated to the EVAR procedure, 1 of a massive cerebral ischemic event, 1 patient with hemophilia suffered sudden death after an urological procedure, 1 of pulmonary infection, and finally 3 patients died because of oncological reason.
DISCUSSION In an era of growing interest, expertise and good results in complex fenestrated/branched EVAR for short-necked aortic aneurysms, the Ovation
Volume
-, -
2019
Mid-term outcome of the Ovation stent graft 5
Fig. 2. (A) Kaplan-Meier estimate of the cumulative patient survival during follow-up. (B) Kaplan-Meier estimate of the freedom from device-related intervention during follow-up.
technology redefines the idea of hostile neck for standard EVAR.9,10 Fixation and sealing are maintained by 2 different processes. The 35-mm long suprarenal rigid nitinol stents fix at the level of a healthier aorta, whereas the seal is obtained by the proximal gasket-like polymer sealing ring. This sealing ring is located 13 mm below the lowest renal artery.11 Minimal chronic outward force prevents further aortic neck dilation over time.10 All the stent grafts mentioned in Table II state that significant thrombus and/or calcification may affect successful aneurysm exclusion. None of them report on a maximum percentage of thrombus or calcification that is permitted. We believe that additional postballooning within the remodeling phase of the polymer sealing ring will maximize the sealing potential of the graft, especially in case of severe calcification and/or thrombus. Both patients inside (89.2%) and outside IFU (10.8%) were included. Nevertheless, 83% was considered to have a hostile neck. Compared with other stent graft systems, 10.8e 17.5% of our patients could not be treated within IFU (Table II). Four patients (5%) suffered type Ia endoleak on completion angiography, and 3 of them resolved spontaneously on the first CTa, without recurrence. Comparable data are found in the literature. In cases with adherence to the IFU,
spontaneous sealing is described.12 Our patient with the persistent type Ia endoleak despite additional cuff had a reversed tapered neck with an accessory renal artery at the distal neck. Technical success rate was 91.89%. Neither major adverse events nor mortality occurred during the first 30 days. Our technical success rate was lower (91.9%) compared with data reported in the literature, which is 96.5e100%.5,10,13,14 We assign this rate to the high number of challenging necks in our series. Current literature reports good clinical results in a short-term to mid-term follow-up period as depicted in Table IV. We report the first mid-term to long-term follow-up results. Mean follow-up time was 31.62 months ± 21.3 (range, 0e72.74). Twenty-four patients had a follow-up time of at least 36 months, 19 patients had a follow-up time of at least 48 months, and 12 patients had a follow-up time for at least 5 years. No patient was lost to follow-up. Mid-term results were already published with a maximum follow-up time of 50 months.14 At 5 years, estimated freedom from mortality rate was 68.5%. No aneurysm-related mortality was seen. In contrast to real-world data of other stent grafts, no late type Ia endoleak was seen.20 The absence of aortic neck dilation with stent grafts without chronic outward force was already observed with a
6 Mufty et al.
Annals of Vascular Surgery
Table IV. Current published literature
Study
Storck et al.5
Mean follow-up time Patients (N ) (months)
Technical success (%)
Freedom from aneurysmLate type related 1a endoleak mortality (%) Secondary interventions
12
M: 100 F: 99.5
M: 1.5% F: 0%
M: 100 F: 99.3
M: 27/432 F: 8/69
Sirignano et al.13
501 M: 86% F: 14% 156
20.4 ± 8.8 (1e60)
100
1.3%
e
Mazzaccaro et al.15 Krajcer et al.16
30 250
15.2 (1e56.7) 93.3 1 100
100 100
Ioannou et al.17
66
13 (2e39)
95
2/30 1/250 <1 month 0/66
6/156 2: embolization type II endoleak 4: iliac/femoral occlusive disease 2/30 0
Ierardi et al.18 Greaves et al.1
n ¼ 36 n ¼ 52
100 100
0/36 0/53
100 100
de Donato et al.10 de Donato et al.14
27.7 (24e37) Median 24 (3e48) 32 (24e50) 32 (24e50)
n ¼ 161 n ¼ 89 IFU group, n ¼ 57 Off-label group, n ¼ 32 n ¼ 42 7.8 ± 4.6 n ¼ 74 32 ± 21.3 (0e72.7)
98.1 IFU group: 96.5 Off-label group: 96.9
3/161 2/89 IFU group: 1/57 Off-label group: 1/32 0/42 0/74
100 100
8/161 5/89 IFU group: 4/57 Off-label group: 1/57
100 100
2/42 10/74
Trellopoulos et al.19 Mufty et al.
100 91.9
100
15% Endo: n ¼ 6 (9%) Open: n ¼ 4 (6%) 0 1/52
M, men; F, Female.
core laboratory analysis in 161 patients after a minimum follow-up time of 24 months.10 One 91-yearold patient presented with a late (after 31 months) symptomatic type Ib endoleak in a 25-mm iliac limb on the left side. This could be relined successfully. Freedom from device-related reintervention at 3 and 5 years was 80.1%. In the longer followup period, no additional interventions were needed after 31.6 months of follow-up. Patients at risk after this period were 28. Although numbers are small, our study suggests that the Ovation stent graft seems to be safe and effective in avoiding aneurysmrelated death on the mid term to long term. No limb thrombosis was seen during follow-up although 1 case required relining because of kinking with symptoms of claudication of the lower limb. The same results are described by Greaves et al.1 after a median follow-up time of 24 months. Other articles also reported low rates from 0.02% to 0.8% in the early term and mid-term follow-up period.10,13,14,16 A recent meta-analysis including a
total of 5,454 patients showed a pooled incidence estimate of primary iliac limb occlusion of 5.6%, whereas the incidence was more pronounced in older studies. The Ovation stent graft was not included in this study.21 Finally, there are some limitations to our study to highlight. First of all, outcome results should be interpreted with care as not all patients suitable for EVAR procedure were treated with an Ovation stent graft in our institution. In particular, when challenging neck was present, the Ovation stent graft was the preferred device. Second, no ruptured cases were included in our study. Third, because of the retrospective character of the study, exact cause of death was unknown in 5 patients. Fourth, according to our follow-up protocol, patients were followed up with DUS and X-ray if no endoleak was seen after 1 year. New type I or III endoleaks with stable diameter could be missed with this surveillance protocol. According to the current guidelines, annual DUS after early postoperative CTa is sufficient to detect
Volume
-, -
2019
clinical relevant type I or III endoleaks.6,22,23 Compared with DUS, contrast-enhanced ultrasound has a higher sensitivity. Specificity is very high for both type I and type III endoleaks.24 Finally, no comparison to other stent graft was performed. Larger study population is mandatory to demonstrate noninferiority to other stent grafts.25 In conclusion, this report demonstrated durable and safe mid-term to long-term outcome results without late type Ia or type III endoleak. REFERENCES 1. Greaves NS, Moore A, Seriki D, et al. Outcomes of endovascular aneurysm repair using the ovation stent graft system in adverse anatomy. Eur J Vasc Endovasc Surg 2018;55:512e7. 2. Sirignano P, Capoccia L, Menna D, et al. Pushing forward the limits of EVAR: new therapeutic solutions for extremely challenging AAAs using the Ovation(R) stent-graft. J Cardiovasc Surg (Torino) 2016;57:839e45. 3. Georgakarakos E, Ioannou CV, Trellopoulos G, et al. Immediate change in suprarenal neck angulation after endovascular aneurysm repair: comparison of the ovation stent-graft inflatable sealing rings to a conventional self-expanding stent-graft. J Endovasc Ther 2015;22:613e9. 4. Koutsoumpelis A, Georgakarakos E, Tasopoulou KM, et al. A clinical update on the mid-term clinical performance of the Ovation endograft. Expert Rev Med Devices 2019;16:57e62. 5. Storck M, Nolte T, Tenholt M, et al. Women and men derive comparable benefits from an ultra-low-profile endograft: 1year results of the European OVATION registry. J Cardiovasc Surg (Torino) 2017;58:658e64. 6. Wanhainen A, Verzini F, Van Herzeele I, et al. Editor’s ChoicedEuropean Society for Vascular Surgery (ESVS) 2019 clinical practice guidelines on the management of abdominal aorto-iliac artery aneurysms. Eur J Vasc Endovasc Surg 2019;57:8e93. 7. Harris PL, Buth J, Mialhe C, et al. The need for clinical trials of endovascular abdominal aortic aneurysm stent-graft repair: the EUROSTAR Project. EUROpean collaborators on Stent-graft Techniques for abdominal aortic Aneurysm Repair. J Endovasc Surg 1997;4:72e7. discussion 78e9. 8. Maleux G, Houthoofd S, Poorteman L, et al. Atypical endoleak associated with inadvertent cannulation of the ipsilateral gate in an ovation trimodular stent-graft. Vasc Endovascular Surg 2018;52:135e7. 9. Katsargyris A, Oikonomou K, Kouvelos G, et al. Comparison of outcomes for double fenestrated endovascular aneurysm repair versus triple or quadruple fenestrated endovascular aneurysm repair in the treatment of complex abdominal aortic aneurysms. J Vasc Surg 2017;66:29e36. 10. de Donato G, Setacci F, Bresadola L, et al. Aortic neck evolution after endovascular repair with TriVascular Ovation stent graft. J Vasc Surg 2016;63:8e15. 11. Georgakarakos E, Ioannou CV, Georgiadis GS, et al. The ovation abdominal stent graft for the treatment of abdominal aortic aneurysms: current evidence and future perspectives. Expert Rev Med Devices 2016;13:253e62.
Mid-term outcome of the Ovation stent graft 7
12. Kontopodis N, Tavlas E, Galanakis N, et al. Spontaneous type Ia endoleak sealing in patients undergoing endovascular aneurysm repair with the ovation stent graft. Ann Vasc Surg 2019;54:240e7. 13. Sirignano P, Mansour W, Pranteda C, et al. Real-life experience with ovation stent graft: lesson learned from the first one hundred fifty treated patients. Ann Vasc Surg 2017;45:253e61. 14. de Donato G, Setacci F, Bresadola L, et al. Midterm results of proximal aneurysm sealing with the ovation stent-graft according to on- vs off-label use. J Endovasc Ther 2017;24: 191e7. 15. Mazzaccaro D, Malacrida G, Amato B, et al. Preliminary experience with the use of ultra-low profile endografts. Diagn Interv Radiol 2017;23:448e53. 16. Krajcer Z, Ramaiah VG, Henao EA, et al. Perioperative outcomes from the prospective multicenter Least Invasive FastTrack EVAR (LIFE) Registry. J Endovasc Ther 2018;25: 6e13. 17. Ioannou CV, Kontopodis N, Kehagias E, et al. Endovascular aneurysm repair with the Ovation TriVascular Stent Graft System utilizing a predominantly percutaneous approach under local anaesthesia. Br J Radiol 2015;88:20140735. 18. Ierardi AM, Tsetis D, Ioannou C, et al. Ultra-low profile polymer-filled stent graft for abdominal aortic aneurysm treatment: a two-year follow-up. Radiol Med 2015;120: 542e8. 19. Trellopoulos G, Georgakarakos E, Pelekas D, et al. Initial single-center experience with the Ovation stent-graft system in the treatment of abdominal aortic aneurysms: application to challenging iliac access anatomies. Ann Vasc Surg 2015;29:913e9. 20. Howard DPJ, Marron CD, Sideso E, et al. Editor’s Choiced Influence of proximal aortic neck diameter on durability of aneurysm sealing and overall survival in patients undergoing endovascular aneurysm repair. Real world data from the Gore Global Registry for Endovascular Aortic Treatment (GREAT). Eur J Vasc Endovasc Surg 2018;56:189e99. 21. Hammond A, Hansrani V, Lowe C, et al. Meta-analysis and meta-regression analysis of iliac limb occlusion after endovascular aneurysm repair. J Vasc Surg 2018;68: 1916e1924.e7. 22. Chaikof EL, Dalman RL, Eskandari MK, et al. The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. J Vasc Surg 2018;67: 2e77.e2. 23. Erbel R, Aboyans V, Boileau C, et al. 2014 ESC Guidelines on the diagnosis and treatment of aortic diseases: document covering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adult. The Task Force for the Diagnosis and Treatment of Aortic Diseases of the European Society of Cardiology (ESC). Eur Heart J 2014;35: 2873e926. 24. Zaiem F, Almasri J, Tello M, et al. A systematic review of surveillance after endovascular aortic repair. J Vasc Surg 2018;67:320e331.e337. 25. Kent F, Ambler GK, Bosanquet DC, et al. The safety of device registries for endovascular abdominal aortic aneurysm repair: systematic review and meta-regression. Eur J Vasc Endovasc Surg 2018;55:177e83.
Background: To report mid-term to long-term outcome data for endovascular aortic repair using the Ovation stent-graft system (Endologix, Santa Rosa, CA) in a single university center. Methods: All patients treated with the Ovation stent graft between February 2012 and January 2019 were included. Patient demographics, anatomical and operative details, as well as followup data including complications, need for further interventions, and mortality were analyzed. Results: A total of 74 patients (93% males; mean age, 74.5 years) were treated with the Ovation stent graft. The median maximal aortic diameter was 60 mm (range, 36e100). Sixtytwo of 74 patients (83.8%) were considered to have a hostile neck. About 33% had a (reversed) conical neck, 59% had circumferential neck calcification (>50%), and 39% had significant neck thrombus (>50%). Technical success rate was 91.89%. Despite additional measures, 4 patients had a persistent type Ia endoleak on completion angiography, of which 3 disappeared on the first postoperative computed tomography angiography. Mean follow-up duration was 31.62 months ± 21.3 (range, 0e72.74 months). Twenty-four patients had a follow-up time of at least 36 months. Freedom from reintervention at 1, 2, 3, and 5 years was 92.7%, 90.8%, 80.1%, and 80.1%, respectively. Estimated freedom from mortality at 1, 2, 3, and 5 years was 96.8%, 95.0%, 87.3%, and 68.5%, respectively. No late type Ia or type III endoleak was detected during follow-up. No aneurysm-related mortality was seen. Conclusions: Our mid- to long-term experience with the Ovation stent-graft system demonstrates safe and durable results without late type Ia or type III endoleak.
INTRODUCTION The Ovation stent-graft system (Endologix, Santa Rosa, CA) is an endoprosthesis with a trimodular Conflicts of interest: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The hospital receives consultancy fees for Ovation workshops. Ethical approval: Ethical approval was obtained by the local ethics committee of the hospital (S62135). 1 Department of Vascular Surgery, University Hospitals Leuven, Leuven, Belgium. 2 Department of Radiology, University Hospitals Leuven, Leuven, Belgium.
Correspondence to: Hozan Mufty, MD, Department of Vascular Surgery, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium; E-mail: [email protected] @UZLeuven Ann Vasc Surg 2019; -: 1–7 https://doi.org/10.1016/j.avsg.2019.06.045 Ó 2019 Elsevier Inc. All rights reserved. Manuscript received: May 7, 2019; manuscript accepted: June 28, 2019; published online: - - -
design for the treatment of infrarenal aortic aneurysms. The suprarenal nitinol stent with integrated anchors for fixation in combination with inflatable polymer-filled sealing rings has already proven to extend the on-label eligibility criteria for endovascular aortic repair (EVAR).1,2 In contrast to stentsupported endograft sealing, these sealing rings are not associated with aortic neck dilation.3 The low profile 14F delivery system allows treatment of abdominal aortic aneurysms with small or narrowed in-diameter access vessels. Since the introduction of the Ovation stent-graft system, delivery system enhancements (ultra-low profile design, integrated sheath) are introduced. Ovation, Ovation Prime, and finally Ovation iX with the built-in procedural option to facilitate contralateral limb placement have already proven to have a safe outcome with very satisfactory early and mid-term results.1,4 Until now, long-term outcome results and comparative 1
2 Mufty et al.
studies are lacking.1,4e6 In this retrospective study, we present our single-center mid-term to longterm outcome results with the use of the Ovation, Ovation Prime, and Ovation iX stent-graft system during 6 years.
MATERIALS AND METHODS All patients treated with the Endologix Ovation platform (including Ovation, Ovation Prime, and Ovation iX Abdominal stent-graft system) between February 2012 and January 2019 in a single center university hospital were retrospectively analyzed from a prospective database. All patients gave informed consent before the EVAR procedure, both for the procedure and the follow-up scheme as defined by the Belgian National Health insurance Office. No ruptured cases were treated with this stent-graft system. In our center, open surgery is recommended for minimal risk young patients and medium-risk to high-risk patients with unsuitable anatomy for standard or complex fenestrated or branched EVAR. In our center, different stent-graft types are used. Challenging necks are preferably treated with the Ovation stent graft. Patients within both inside and outside the instructions for use (IFU) were included. Criteria for treatment were an aortic diameter 55 mm in men or 50 mm in women and fast growth (>5 mm in 6 months). Patients were considered to have a hostile aortic neck anatomy if: infrarenal neck angulation was 60, neck length <10 mm, infrarenal aortic diameter <16 mm or >30 mm, and unfavorable neck shape, such as conical, reversed conical, >50% calcification, and circular or semicircular thrombus. Preoperative imaging was performed by computed tomography angiography (CTa). In case of severe renal insufficiency magnetic resonance angiography in combination with unenhanced CT to display calcified plaques was performed. In these cases, procedures were performed with the use of carbon dioxide angiography. Procedures were performed in a hybrid operating room with a fixed c-arm system (Artis Zeego; Siemens AG, Forchheim, Germany). Under local or general anesthesia, femoral access was performed both through surgical cutdown and/or by an endovascular approach with the use of a closure device. Technical success was defined as successful deployment of the stent graft without type I or III endoleak, successful removal of the delivery system, and no unintentional coverage of visceral aortic branches or hypogastric arteries. Our follow-up protocol consisted of a clinical checkup 4 weeks postoperatively and a CTa after 3
Annals of Vascular Surgery
Table I. Patient demographics Characteristics
n (%)
Male/female Hypercholesterolemia Arterial hypertension BMI Smoking Never Active Ceased Peripheral arterial disease Coronary artery disease Chronic kidney disease (eGFR <60 mL/min) Cerebrovascular disease Diabetes No Insulin dependent Noninsulin dependent ASA classification I II III IV Medication Antiaggregant Anticoagulant
69 (93)/5 (7) 65 (88) 57 (77) 27.85 ± 4.0 17 16 41 16 35 20
(23) (22) (55) (22) (47) (27)
7 (9) 60 (81) 2 (3) 12 (16) 1 11 54 8
(1) (15) (73) (11)
58 (79) 7 (10)
BMI, body mass index; eGFR, estimated glomerular filtration rate; ASA, American Society of Anesthesiologists.
months and 1 year. In accordance to the EUROpean collaborators on Stent-graft Techniques for abdominal aortic Aneurysm Repair criteria,7 if no endoleak was seen and the aortic diameter remained stable or decreased, further follow-up was performed by annual duplex ultrasound (DUS) and abdominal X-ray. Patients with persistent signs of endoleak were further followed by CTa. Stent graft migration, endoleaks, reinterventions, and time and cause of death were recorded. SPSS for Windows (version 25; SPSS Inc, Chicago, IL) was used for statistical analysis. Variables are presented as mean ± standard deviation in case of normal distribution and median + range in case of skewed distribution. Kaplan-Meier estimate was used to define survival and reintervention during follow-up.
RESULTS Between February 2012 and January 2019, 74 patients (mean age, 74.5 years ± 7.68) were treated with the Endologix Ovation platform for infrarenal aortic disease. Patient demographics are reported in Table I. Most patients presented with a fusiform
Volume
-, -
2019
Mid-term outcome of the Ovation stent graft 3
Table II. IFU of different stent grafts
Graft
Neck length (mm)
E-Tegra (Jotec, Hechingen, Germany) Zenith-Alpha (Cook Medical, Bloomington, IN) Gore C3 (W.L. Gore & Associates, Flagstaff, AZ) Incraft (Cardinal Health, Dublin, Ireland) Endurant II (Medtronic, Santa Rosa, CA) Ovation iX (Endologix, Santa Rosa, CA)
15 15 15 10 10 10 if aortic angle 60 <10 if aortic angle 45
Diameter Neck proximal Alfa diameter landing angle Patients outside (mm) IFU, n/N (%) zone (mm) ( )
19e32 18e32 19e32 17e31 19e32 16e30
8e25 7.5e20 8e25 7e22 8e25 8e25
75 <60 <60 60 <60
8/74 13/74 13/74 10/74 11/74 8/74
(10.8) (17.5) (17.5) (13.5) (14.8) (10.8)
Fig. 1. (A and B) An 84-year-old patient with semicircular neck thrombus on preoperative and postoperative CTa. (C) A 79-year-old patient with renal insufficiency
and significant aortic neck calcification preoperatively. (D) Postoperative CTa showing good apposition of the polymer-filled sealing ring.
infrarenal aortic aneurysm (n ¼ 70; 95%). The 4 remaining patients were treated for a saccular aneurysm of the aorta. The median maximal aortic diameter was 60 mm (range, 36e100). Patients with maximal aortic diameter <55 mm for men and
<50 for women were treated for saccular aneurysm. The number of patients treated within IFU is depicted in Table II. Angulation was the only reason to be outside IFU in our study group. Sixty-two of 74 patients (83.8%) were considered to have a hostile
4 Mufty et al.
Annals of Vascular Surgery
Table III. Aneurysm characteristics Mean neck diameter Median neck length Mean aortic neck angulation Hostile neck, n/N (%) Significant neck calcification Circular neck thrombus Semicircular neck thrombus Neck morphology Tapered Reversed tapered
23.37 mm ± 3.28 32 mm (range, 13e79) 33 ± 18.96 (range, 3e80) 62/74 (83.8) 44/74 (59) 9/74 (12) 20/74 (27) 7/74 (9) 18/74 (24)
neck (Fig. 1). Aneurysm characteristics are provided in Table III. Two of 74 patients needed preoperative coiling of a hypogastric artery to create a safe distal sealing zone. One patient had a very large caliber inferior mesenteric artery that was occluded preoperatively with an Amplatzer vascular plug (St Jude Medical, St Paul, MN). One patient with peripheral arterial disease required an iliofemoral bypass through groin incision, and 2 patients needed balloon angioplasty of the iliac artery to make delivery of the endograft possible. Technical success rate was 91.89%. One patient needed additional limb relining and stenting because of persistent kinking/stenosis. Despite additional measures such as ballooning, 4 patients had a persistent type Ia endoleak on completion angiography. In this group, 1 patient received an Excluder aortic cuff (W.L. Gore & Associates, Flagstaff, AZ) because of a low release of the stent graft. One patient had type Ib endoleak, and 1 patient had type III endoleak. The latter patient received additional kissing Advanta V12 (Atrium Maquet Getinge Group, Mijdrecht, The Netherlands) without resolution of the endoleak. Three of 4 type Ia endoleaks and type Ib endoleak disappeared spontaneously on the first postoperative CTa. In the patient with the aortic cuff, type Ia endoleak was still present on the first CTa with outflow over the inferior mesenteric artery. This could be successfully treated with Onyx and coils. Twenty-two months postoperatively, a stable aortic diameter was seen with no signs of endoleak. The patient with type III endoleak was a 55-year-old male with an aortic aneurysm of 64 mm. Because of comorbidities, an endovascular approach was preferred. On the first postoperative CTa, it became clear that the operation was complicated by inadvertent bilateral iliac limb insertion into the right gate without cannulation of the left gate. The left outflow inferior mesenteric artery was coil embolized, and the inflow left gate was closed with an Amplatzer plug.8 Follow-up CTa after 70 months
still showed the absence of any endoleak and a decrease of aortic diameter toward 60 mm. No 30day mortality occurred. Mean follow-up duration was 31.62 months ± 21.3 (range, 0e72.74). Twenty-four patients had a follow-up time of at least 36 months, 19 patients had a follow-up time of at least 48 months, and 12 patients had a follow-up time for at least 5 years. Freedom from reintervention at 1, 2, 3, and 5 years was 92.7% ± 3.1, 90.8% ± 3.6, 80.1% ± 6.0, and 80.1% ± 6.0, respectively (Fig. 1). No limb thrombosis occurred. Three patients received transarterial embolization of type II endoleak, and 2 patients underwent direct embolization of type II endoleak. One patient with extreme calcified aortoiliac disease needed additional groin endarterectomy and endovascular repair of the iliac axis because of ischemic complaints (Rutherford stage 5) after extubation. Another patient with a narrow aortic bifurcation presented 8 days postoperatively at the emergency department with claudication complaints at the left side. CTa revealed a compression of the left limb at the level of the flow divided. This was successfully treated by kissing stenting with 2 Advanta V12 stents. Finally, one 91-year-old patient presented with a symptomatic type Ib endoleak because of progression of aneurysmatic disease of the common iliac artery and concomitant stent migration 31 months postoperatively. This was treated by limb relining. No late type Ia or type III endoleak was detected during follow-up. Estimated freedom from mortality at 1, 2, 3, and 5 years was 96.8% ± 2.2, 95.0% ± 2.8, 87.3% ± 5.0, and 68.5% ± 8.5 (Fig. 2). During follow-up, 13 patients died after a mean follow-up time of 38.1 months (range, 7.3e62.6), and mean age was 79 ± 8.0 years. Five of these 13 patients died during follow-up because of an unknown cause. Nevertheless, no patients were lost to follow-up. Of these 5 patients, only 2 patients had type II endoleak in final follow-up imaging without significant (>5 mm) growth of the aneurysm. One patient died of cardiac decompensation, 1 of pulmonary embolism unrelated to the EVAR procedure, 1 of a massive cerebral ischemic event, 1 patient with hemophilia suffered sudden death after an urological procedure, 1 of pulmonary infection, and finally 3 patients died because of oncological reason.
DISCUSSION In an era of growing interest, expertise and good results in complex fenestrated/branched EVAR for short-necked aortic aneurysms, the Ovation
Volume
-, -
2019
Mid-term outcome of the Ovation stent graft 5
Fig. 2. (A) Kaplan-Meier estimate of the cumulative patient survival during follow-up. (B) Kaplan-Meier estimate of the freedom from device-related intervention during follow-up.
technology redefines the idea of hostile neck for standard EVAR.9,10 Fixation and sealing are maintained by 2 different processes. The 35-mm long suprarenal rigid nitinol stents fix at the level of a healthier aorta, whereas the seal is obtained by the proximal gasket-like polymer sealing ring. This sealing ring is located 13 mm below the lowest renal artery.11 Minimal chronic outward force prevents further aortic neck dilation over time.10 All the stent grafts mentioned in Table II state that significant thrombus and/or calcification may affect successful aneurysm exclusion. None of them report on a maximum percentage of thrombus or calcification that is permitted. We believe that additional postballooning within the remodeling phase of the polymer sealing ring will maximize the sealing potential of the graft, especially in case of severe calcification and/or thrombus. Both patients inside (89.2%) and outside IFU (10.8%) were included. Nevertheless, 83% was considered to have a hostile neck. Compared with other stent graft systems, 10.8e 17.5% of our patients could not be treated within IFU (Table II). Four patients (5%) suffered type Ia endoleak on completion angiography, and 3 of them resolved spontaneously on the first CTa, without recurrence. Comparable data are found in the literature. In cases with adherence to the IFU,
spontaneous sealing is described.12 Our patient with the persistent type Ia endoleak despite additional cuff had a reversed tapered neck with an accessory renal artery at the distal neck. Technical success rate was 91.89%. Neither major adverse events nor mortality occurred during the first 30 days. Our technical success rate was lower (91.9%) compared with data reported in the literature, which is 96.5e100%.5,10,13,14 We assign this rate to the high number of challenging necks in our series. Current literature reports good clinical results in a short-term to mid-term follow-up period as depicted in Table IV. We report the first mid-term to long-term follow-up results. Mean follow-up time was 31.62 months ± 21.3 (range, 0e72.74). Twenty-four patients had a follow-up time of at least 36 months, 19 patients had a follow-up time of at least 48 months, and 12 patients had a follow-up time for at least 5 years. No patient was lost to follow-up. Mid-term results were already published with a maximum follow-up time of 50 months.14 At 5 years, estimated freedom from mortality rate was 68.5%. No aneurysm-related mortality was seen. In contrast to real-world data of other stent grafts, no late type Ia endoleak was seen.20 The absence of aortic neck dilation with stent grafts without chronic outward force was already observed with a
6 Mufty et al.
Annals of Vascular Surgery
Table IV. Current published literature
Study
Storck et al.5
Mean follow-up time Patients (N ) (months)
Technical success (%)
Freedom from aneurysmLate type related 1a endoleak mortality (%) Secondary interventions
12
M: 100 F: 99.5
M: 1.5% F: 0%
M: 100 F: 99.3
M: 27/432 F: 8/69
Sirignano et al.13
501 M: 86% F: 14% 156
20.4 ± 8.8 (1e60)
100
1.3%
e
Mazzaccaro et al.15 Krajcer et al.16
30 250
15.2 (1e56.7) 93.3 1 100
100 100
Ioannou et al.17
66
13 (2e39)
95
2/30 1/250 <1 month 0/66
6/156 2: embolization type II endoleak 4: iliac/femoral occlusive disease 2/30 0
Ierardi et al.18 Greaves et al.1
n ¼ 36 n ¼ 52
100 100
0/36 0/53
100 100
de Donato et al.10 de Donato et al.14
27.7 (24e37) Median 24 (3e48) 32 (24e50) 32 (24e50)
n ¼ 161 n ¼ 89 IFU group, n ¼ 57 Off-label group, n ¼ 32 n ¼ 42 7.8 ± 4.6 n ¼ 74 32 ± 21.3 (0e72.7)
98.1 IFU group: 96.5 Off-label group: 96.9
3/161 2/89 IFU group: 1/57 Off-label group: 1/32 0/42 0/74
100 100
8/161 5/89 IFU group: 4/57 Off-label group: 1/57
100 100
2/42 10/74
Trellopoulos et al.19 Mufty et al.
100 91.9
100
15% Endo: n ¼ 6 (9%) Open: n ¼ 4 (6%) 0 1/52
M, men; F, Female.
core laboratory analysis in 161 patients after a minimum follow-up time of 24 months.10 One 91-yearold patient presented with a late (after 31 months) symptomatic type Ib endoleak in a 25-mm iliac limb on the left side. This could be relined successfully. Freedom from device-related reintervention at 3 and 5 years was 80.1%. In the longer followup period, no additional interventions were needed after 31.6 months of follow-up. Patients at risk after this period were 28. Although numbers are small, our study suggests that the Ovation stent graft seems to be safe and effective in avoiding aneurysmrelated death on the mid term to long term. No limb thrombosis was seen during follow-up although 1 case required relining because of kinking with symptoms of claudication of the lower limb. The same results are described by Greaves et al.1 after a median follow-up time of 24 months. Other articles also reported low rates from 0.02% to 0.8% in the early term and mid-term follow-up period.10,13,14,16 A recent meta-analysis including a
total of 5,454 patients showed a pooled incidence estimate of primary iliac limb occlusion of 5.6%, whereas the incidence was more pronounced in older studies. The Ovation stent graft was not included in this study.21 Finally, there are some limitations to our study to highlight. First of all, outcome results should be interpreted with care as not all patients suitable for EVAR procedure were treated with an Ovation stent graft in our institution. In particular, when challenging neck was present, the Ovation stent graft was the preferred device. Second, no ruptured cases were included in our study. Third, because of the retrospective character of the study, exact cause of death was unknown in 5 patients. Fourth, according to our follow-up protocol, patients were followed up with DUS and X-ray if no endoleak was seen after 1 year. New type I or III endoleaks with stable diameter could be missed with this surveillance protocol. According to the current guidelines, annual DUS after early postoperative CTa is sufficient to detect
Volume
-, -
2019
clinical relevant type I or III endoleaks.6,22,23 Compared with DUS, contrast-enhanced ultrasound has a higher sensitivity. Specificity is very high for both type I and type III endoleaks.24 Finally, no comparison to other stent graft was performed. Larger study population is mandatory to demonstrate noninferiority to other stent grafts.25 In conclusion, this report demonstrated durable and safe mid-term to long-term outcome results without late type Ia or type III endoleak. REFERENCES 1. Greaves NS, Moore A, Seriki D, et al. Outcomes of endovascular aneurysm repair using the ovation stent graft system in adverse anatomy. Eur J Vasc Endovasc Surg 2018;55:512e7. 2. Sirignano P, Capoccia L, Menna D, et al. Pushing forward the limits of EVAR: new therapeutic solutions for extremely challenging AAAs using the Ovation(R) stent-graft. J Cardiovasc Surg (Torino) 2016;57:839e45. 3. Georgakarakos E, Ioannou CV, Trellopoulos G, et al. Immediate change in suprarenal neck angulation after endovascular aneurysm repair: comparison of the ovation stent-graft inflatable sealing rings to a conventional self-expanding stent-graft. J Endovasc Ther 2015;22:613e9. 4. Koutsoumpelis A, Georgakarakos E, Tasopoulou KM, et al. A clinical update on the mid-term clinical performance of the Ovation endograft. Expert Rev Med Devices 2019;16:57e62. 5. Storck M, Nolte T, Tenholt M, et al. Women and men derive comparable benefits from an ultra-low-profile endograft: 1year results of the European OVATION registry. J Cardiovasc Surg (Torino) 2017;58:658e64. 6. Wanhainen A, Verzini F, Van Herzeele I, et al. Editor’s ChoicedEuropean Society for Vascular Surgery (ESVS) 2019 clinical practice guidelines on the management of abdominal aorto-iliac artery aneurysms. Eur J Vasc Endovasc Surg 2019;57:8e93. 7. Harris PL, Buth J, Mialhe C, et al. The need for clinical trials of endovascular abdominal aortic aneurysm stent-graft repair: the EUROSTAR Project. EUROpean collaborators on Stent-graft Techniques for abdominal aortic Aneurysm Repair. J Endovasc Surg 1997;4:72e7. discussion 78e9. 8. Maleux G, Houthoofd S, Poorteman L, et al. Atypical endoleak associated with inadvertent cannulation of the ipsilateral gate in an ovation trimodular stent-graft. Vasc Endovascular Surg 2018;52:135e7. 9. Katsargyris A, Oikonomou K, Kouvelos G, et al. Comparison of outcomes for double fenestrated endovascular aneurysm repair versus triple or quadruple fenestrated endovascular aneurysm repair in the treatment of complex abdominal aortic aneurysms. J Vasc Surg 2017;66:29e36. 10. de Donato G, Setacci F, Bresadola L, et al. Aortic neck evolution after endovascular repair with TriVascular Ovation stent graft. J Vasc Surg 2016;63:8e15. 11. Georgakarakos E, Ioannou CV, Georgiadis GS, et al. The ovation abdominal stent graft for the treatment of abdominal aortic aneurysms: current evidence and future perspectives. Expert Rev Med Devices 2016;13:253e62.
Mid-term outcome of the Ovation stent graft 7
12. Kontopodis N, Tavlas E, Galanakis N, et al. Spontaneous type Ia endoleak sealing in patients undergoing endovascular aneurysm repair with the ovation stent graft. Ann Vasc Surg 2019;54:240e7. 13. Sirignano P, Mansour W, Pranteda C, et al. Real-life experience with ovation stent graft: lesson learned from the first one hundred fifty treated patients. Ann Vasc Surg 2017;45:253e61. 14. de Donato G, Setacci F, Bresadola L, et al. Midterm results of proximal aneurysm sealing with the ovation stent-graft according to on- vs off-label use. J Endovasc Ther 2017;24: 191e7. 15. Mazzaccaro D, Malacrida G, Amato B, et al. Preliminary experience with the use of ultra-low profile endografts. Diagn Interv Radiol 2017;23:448e53. 16. Krajcer Z, Ramaiah VG, Henao EA, et al. Perioperative outcomes from the prospective multicenter Least Invasive FastTrack EVAR (LIFE) Registry. J Endovasc Ther 2018;25: 6e13. 17. Ioannou CV, Kontopodis N, Kehagias E, et al. Endovascular aneurysm repair with the Ovation TriVascular Stent Graft System utilizing a predominantly percutaneous approach under local anaesthesia. Br J Radiol 2015;88:20140735. 18. Ierardi AM, Tsetis D, Ioannou C, et al. Ultra-low profile polymer-filled stent graft for abdominal aortic aneurysm treatment: a two-year follow-up. Radiol Med 2015;120: 542e8. 19. Trellopoulos G, Georgakarakos E, Pelekas D, et al. Initial single-center experience with the Ovation stent-graft system in the treatment of abdominal aortic aneurysms: application to challenging iliac access anatomies. Ann Vasc Surg 2015;29:913e9. 20. Howard DPJ, Marron CD, Sideso E, et al. Editor’s Choiced Influence of proximal aortic neck diameter on durability of aneurysm sealing and overall survival in patients undergoing endovascular aneurysm repair. Real world data from the Gore Global Registry for Endovascular Aortic Treatment (GREAT). Eur J Vasc Endovasc Surg 2018;56:189e99. 21. Hammond A, Hansrani V, Lowe C, et al. Meta-analysis and meta-regression analysis of iliac limb occlusion after endovascular aneurysm repair. J Vasc Surg 2018;68: 1916e1924.e7. 22. Chaikof EL, Dalman RL, Eskandari MK, et al. The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. J Vasc Surg 2018;67: 2e77.e2. 23. Erbel R, Aboyans V, Boileau C, et al. 2014 ESC Guidelines on the diagnosis and treatment of aortic diseases: document covering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adult. The Task Force for the Diagnosis and Treatment of Aortic Diseases of the European Society of Cardiology (ESC). Eur Heart J 2014;35: 2873e926. 24. Zaiem F, Almasri J, Tello M, et al. A systematic review of surveillance after endovascular aortic repair. J Vasc Surg 2018;67:320e331.e337. 25. Kent F, Ambler GK, Bosanquet DC, et al. The safety of device registries for endovascular abdominal aortic aneurysm repair: systematic review and meta-regression. Eur J Vasc Endovasc Surg 2018;55:177e83.