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Editor's Choice – Systematic Review of the Use of Endoanchors in Endovascular Aortic Aneurysm Repair

Open ArchivePublished:March 17, 2020DOI:https://doi.org/10.1016/j.ejvs.2020.02.008

      Objective

      Endoanchor fixation might be a potential adjunct for the prevention and treatment of type Ia endoleak (TIaE) and graft migration in thoracic or abdominal endovascular aortic aneurysm repairs (TEVAR or EVAR). This review aimed to explore the safety and effectiveness of endoanchor fixation in TEVAR and EVAR.

      Methods

      A systematic review and random effects meta-analysis was conducted. Data sources were PubMed/MEDLINE, Embase, and the Cochrane Library.

      Results

      Seven EVAR and three TEVAR studies using the Heli-FX™ EndoAnchor™ system were included in the meta-analysis. A total of 455 EVAR patients underwent primary endoanchor fixation. Technical success was 98.4% (95% CI 95.7–99.8%). The rate of TIaE and graft migration was 3.5% (95% CI 1.7–5.9%) and 2.0% (95% CI 0.12–6.0%), respectively, after 15.4 months (95% CI 1.76–29.0) follow up. A total of 107 EVAR patients underwent secondary fixation with a technical success of 91.8% (95% CI 86.1–96.2%). Rates of TIaE and graft migration were 22.6% (95% CI 9.1–40.0%) and 0% after a mean 10.7 month (95% CI 7.8–13.6) follow up. Adverse events included three endoanchor fractures, three dislocated endoanchors, one entrapped endoanchor, and one common iliac artery dissection. All cause 30 day EVAR mortality was 0.82% (95% CI 0.20–1.85%). Sixty-six TEVAR patients underwent endoanchor fixation with a mean 9.8 month (95% CI 8.1–11.5) follow up. Technical success was 90.3% (95% CI 72.1–99.4%). The rates of TIaE and migration were 8.7% (95% CI 1.0–18.9%) and 0%, respectively. Adverse events included two misdeployed endoanchors with one fatal aortic dissection. All cause 30 day TEVAR mortality was 11.9% (95% CI 5.4–20.6%).

      Conclusion

      Endoanchor fixation in EVAR is technically feasible and safe, with at least comparable early outcomes to the latest generation of stent grafts. Endostapling in TEVAR is associated with lower technical success, higher peri-operative mortality, and potential serious adverse events. Current evidence lacks long term follow up and case controlled trials to recommend endoanchor use in routine practice.

      Keywords

      This systematic review and meta-analysis summarises the evidence for endoanchor use in EVAR and TEVAR to treat type Ia endoleak (TIaE) and graft migration. Endoanchor fixation in EVAR is technically feasible with at least comparable early outcomes to the latest generation of stent grafts in treating TIaE and graft migration. Evidence for endostapling in TEVAR is sparse, and results show lower technical success, higher peri-operative mortality, and potential serious adverse events. The current evidence is limited by short term data and a lack of case controlled trials. Further robust studies are required before endoanchor use can be recommended in routine clinical practice.

      Introduction

      Since its inception in 1991, endovascular aortic aneurysm repair (EVAR) has proved to be a successful, safe, and popular alternative to open aneurysm repair.
      • Parodi J.C.
      • Palmaz J.C.
      • Barone H.D.
      Transfemoral intraluminal graft implantation for abdominal aortic aneurysms.
      Advances in stent graft technology have broadened the scope of patients being treated by EVAR, including those with thoracic aortic aneurysms and challenging aortic neck anatomy. With the advent of fenestrated and chimneys grafts as well as proximal aortic cuffs, good results have been achieved in patients with challenging aortic necks. Despite these developments, proximal neck anatomy remains a key factor to the success of endovascular repair. The quality of the neck is critical in providing an adequate sealing zone to prevent Type Ia endoleak (TIaE) and graft migration.
      • Kouvelos G.N.
      • Spanos K.
      • Nana P.
      • Koutsias S.
      • Rousas N.
      • Giannoukas A.
      • et al.
      Large diameter (≥29 mm) proximal aortic necks are associated with increased complication rates after endovascular repair for abdominal aortic aneurysm.
      • Oliveira N.F.G.
      • Gonçalves F.B.
      • Ultee K.
      • Pinto J.P.
      • Josee van Rijn M.
      • Raa S.T.
      • et al.
      Patients with large neck diameter have a higher risk of type IA endoleaks and aneurysm rupture after standard endovascular aneurysm repair.
      • McFarland G.
      • Tran K.
      • Virgin-Downey W.
      • Sgroi M.D.
      • Chandra V.
      • Mell M.W.
      • et al.
      Infrarenal endovascular aneurysm repair with large device (34- to 36-mm) diameters is associated with higher risk of proximal fixation failure.
      Endoanchors were developed as adjuncts to overcome such complications occurring at the proximal landing zone, particularly in patients with a challenging aortic neck. Endoanchors secure the stent graft mechanically to the aortic wall by means of a metallic “tack,” which penetrates both the stent graft fabric and the adjacent aortic wall. Much of the current data come from the ANCHOR registry, which is the largest ongoing multicentre trial using the Heli-FX™ Endoanchor™ System (Medtronic Vascular, CA, USA).
      • Jordan W.D.
      • Mehta M.
      • Varnagy D.
      • Moore W.M.
      • Arko F.R.
      • Joye J.
      • et al.
      Results of the ANCHOR prospective, multicenter registry of EndoAnchors for type Ia endoleaks and endograft migration in patients with challenging anatomy.
      Endoanchors have been used most commonly during the primary deployment of endografts, to prevent and treat TIaE or migration occurring at the time of stent deployment.
      • Deaton D.H.
      • Mehta M.
      • Kasirajan K.
      • Chaikof E.
      • Farber M.
      • Glickman M.H.
      • et al.
      The phase I multicenter trial (STAPLE-1) of the Aptus endovascular repair system: results at 6 months and 1 year.
      • Mehta M.
      • Henretta J.
      • Glickman M.
      • Deaton D.
      • Naslund T.C.
      • Gray B.
      • et al.
      Outcome of the pivotal study of the Aptus endovascular abdominal aortic aneurysms repair system.
      • Perdikides T.
      • Melas N.
      • Lagios K.
      • Saratzis A.
      • Siafakas A.
      • Bountouris I.
      • et al.
      Primary endoanchoring in the endovascular repair of abdominal aortic aneurysms with an unfavorable neck.
      • Galiñanes E.L.
      • Hernandez E.
      • Krajcer Z.
      Preliminary results of adjunctive use of endoanchors in the treatment of short neck and pararenal abdominal aortic aneurysms.
      • Valdivia A.R.
      • Beropoulis E.
      • Pitoulias G.
      • Pratesi G.
      • Alvarez Marcos F.
      • Barbante M.
      • et al.
      Multicenter registry about the use of endoanchors in the endovascular repair of abdominal aortic aneurysms with hostile neck showed successful but delayed endograft sealing within intraoperative type ia endoleak cases.
      • Giudice R.
      • Borghese O.
      • Sbenaglia G.
      • Coscarella C.
      • Gregorio C.D.
      • Leopardi M.
      • et al.
      The use of EndoAnchors in endovascular repair of abdominal aortic aneurysms with challenging proximal neck: single-centre experience.
      • de Vries J.P.
      • Ouriel K.
      • Mehta M.
      • Varnagy D.
      • Moore W.M.
      • Arko F.R.
      • et al.
      Analysis of EndoAnchors for endovascular aneurysm repair by indications for use.
      • Goudeketting S.R.
      • van Noort K.
      • Ouriel K.
      • Jordan W.D.
      • Panneton J.M.
      • Slump C.H.
      • et al.
      Influence of aortic neck characteristics on successful aortic wall penetration of EndoAnchors in therapeutic use during endovascular aneurysm repair.
      • Ho V.T.
      • George E.L.
      • Dua A.
      • Lavingia K.S.
      • Sgroi M.D.
      • Dake M.D.
      • et al.
      Early real-world experience with endoanchors by indication.
      • Oikonomou K.
      • Kasprzak P.
      • Schierling W.
      • Kopp R.
      • Pfister K.
      Indications for the use of endoanchors: state of the art.
      Endoanchors are also used in secondary procedures to manage similar delayed complications.
      • Giudice R.
      • Borghese O.
      • Sbenaglia G.
      • Coscarella C.
      • Gregorio C.D.
      • Leopardi M.
      • et al.
      The use of EndoAnchors in endovascular repair of abdominal aortic aneurysms with challenging proximal neck: single-centre experience.
      ,
      • Goudeketting S.R.
      • van Noort K.
      • Ouriel K.
      • Jordan W.D.
      • Panneton J.M.
      • Slump C.H.
      • et al.
      Influence of aortic neck characteristics on successful aortic wall penetration of EndoAnchors in therapeutic use during endovascular aneurysm repair.
      • Ho V.T.
      • George E.L.
      • Dua A.
      • Lavingia K.S.
      • Sgroi M.D.
      • Dake M.D.
      • et al.
      Early real-world experience with endoanchors by indication.
      • Oikonomou K.
      • Kasprzak P.
      • Schierling W.
      • Kopp R.
      • Pfister K.
      Indications for the use of endoanchors: state of the art.
      • Avci M.
      • Vos J.A.
      • Kolvenbach R.R.
      • Verhoeven E.L.
      • Perdikides T.
      • Resch T.A.
      • et al.
      The use of endoanchors in repair EVAR cases to improve proximal endograft fixation.
      The majority of cases are performed in conventional abdominal EVAR, but endoanchors have also been used in thoracic endovascular aneurysm repair (TEVAR).
      • Ho V.T.
      • George E.L.
      • Dua A.
      • Lavingia K.S.
      • Sgroi M.D.
      • Dake M.D.
      • et al.
      Early real-world experience with endoanchors by indication.
      ,
      • Oikonomou K.
      • Kasprzak P.
      • Schierling W.
      • Kopp R.
      • Pfister K.
      Indications for the use of endoanchors: state of the art.
      ,
      • Kasprzak P.
      • Pfister K.
      • Janotta M.
      • Kopp R.
      EndoAnchor placement in thoracic and thoracoabdominal stent-grafts to repair complications of nonalignment.
      ,
      • Ongstad S.B.
      • Miller D.F.
      • Panneton J.M.
      The use of EndoAnchors to rescue complicated TEVAR procedures.
      This article reviews the available evidence for endoanchor use in EVAR and TEVAR.

      Methods

      A systematic review was conducted according to the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement.
      • Moher D.
      • Liberati A.
      • Tetzlaff J.
      • Altman D.G.
      • Group P.
      Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement.
      The literature search covered PubMed/MEDLINE, Embase, and Cochrane databases.
      The following multilevel keyword search was used: [“endostaple” or “endoanchor”] and [“aortic aneurysm” or “endovascular aneurysm repair” or “endovascular aortic repair” or “EVAR” or “TEVAR”]. The literature search was concluded on 20 June 2019. There were no language limitations.
      Two investigators (ZQ and TB) independently performed the literature search, study selection, data extraction, and quality evaluation. Study quality assessment was undertaken using the Newcastle–Ottawa tool.
      • Wells G.A.
      • Shea B.
      • O'Connell D.
      • Peterson J.
      • Welch D.
      • Losos M.
      • et al.
      The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses.
      Conflicting results were resolved through discussion between article authors, to reach consensus.

      Study selection

      Database records were imported to Rayyan's QCRI systematic review tool for study screening and selection.
      • Ouzzani M.
      • Hammady H.
      • Fedorowicz Z.
      • Elmagarmid A.
      Rayyan - a web and mobile app for systematic reviews.
      Studies were selected if they met the following inclusion criteria:
      • 1.
        Original cohort studies of patients who underwent EVAR or TEVAR with endoanchor fixation.
      • 2.
        Outcome measures included descriptive rates of TIaE, graft migration, and complications post-endoanchor fixation.
      Multiple publications corresponding to a single cohort study were considered to be part of a single entity. Scientific abstract articles, studies of five or fewer patients, and pre-clinical studies were excluded.
      A total of 195 articles was identified in the initial literature search, with 86 articles remaining after elimination of duplicates. Of these, 77 articles proceeded to full text evaluation. Inclusion criteria were met by 14 single arm, open label studies (Fig. 1, Table 1).
      • Deaton D.H.
      • Mehta M.
      • Kasirajan K.
      • Chaikof E.
      • Farber M.
      • Glickman M.H.
      • et al.
      The phase I multicenter trial (STAPLE-1) of the Aptus endovascular repair system: results at 6 months and 1 year.
      • Mehta M.
      • Henretta J.
      • Glickman M.
      • Deaton D.
      • Naslund T.C.
      • Gray B.
      • et al.
      Outcome of the pivotal study of the Aptus endovascular abdominal aortic aneurysms repair system.
      • Perdikides T.
      • Melas N.
      • Lagios K.
      • Saratzis A.
      • Siafakas A.
      • Bountouris I.
      • et al.
      Primary endoanchoring in the endovascular repair of abdominal aortic aneurysms with an unfavorable neck.
      • Galiñanes E.L.
      • Hernandez E.
      • Krajcer Z.
      Preliminary results of adjunctive use of endoanchors in the treatment of short neck and pararenal abdominal aortic aneurysms.
      • Valdivia A.R.
      • Beropoulis E.
      • Pitoulias G.
      • Pratesi G.
      • Alvarez Marcos F.
      • Barbante M.
      • et al.
      Multicenter registry about the use of endoanchors in the endovascular repair of abdominal aortic aneurysms with hostile neck showed successful but delayed endograft sealing within intraoperative type ia endoleak cases.
      • Giudice R.
      • Borghese O.
      • Sbenaglia G.
      • Coscarella C.
      • Gregorio C.D.
      • Leopardi M.
      • et al.
      The use of EndoAnchors in endovascular repair of abdominal aortic aneurysms with challenging proximal neck: single-centre experience.
      • de Vries J.P.
      • Ouriel K.
      • Mehta M.
      • Varnagy D.
      • Moore W.M.
      • Arko F.R.
      • et al.
      Analysis of EndoAnchors for endovascular aneurysm repair by indications for use.
      • Goudeketting S.R.
      • van Noort K.
      • Ouriel K.
      • Jordan W.D.
      • Panneton J.M.
      • Slump C.H.
      • et al.
      Influence of aortic neck characteristics on successful aortic wall penetration of EndoAnchors in therapeutic use during endovascular aneurysm repair.
      • Ho V.T.
      • George E.L.
      • Dua A.
      • Lavingia K.S.
      • Sgroi M.D.
      • Dake M.D.
      • et al.
      Early real-world experience with endoanchors by indication.
      • Oikonomou K.
      • Kasprzak P.
      • Schierling W.
      • Kopp R.
      • Pfister K.
      Indications for the use of endoanchors: state of the art.
      • Avci M.
      • Vos J.A.
      • Kolvenbach R.R.
      • Verhoeven E.L.
      • Perdikides T.
      • Resch T.A.
      • et al.
      The use of endoanchors in repair EVAR cases to improve proximal endograft fixation.
      • Kasprzak P.
      • Pfister K.
      • Janotta M.
      • Kopp R.
      EndoAnchor placement in thoracic and thoracoabdominal stent-grafts to repair complications of nonalignment.
      • Ongstad S.B.
      • Miller D.F.
      • Panneton J.M.
      The use of EndoAnchors to rescue complicated TEVAR procedures.
      ,
      • Donas K.P.
      • Torsello G.
      Midterm results of the Anson Refix endostapling fixation system for aortic stent-grafts.
      The median Newcastle–Ottawa score was 5 (range 5–6) (Table S1).
      Figure 1
      Figure 1Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram for identification and screening of studies of endoanchors in patients undergoing endovascular aortic aneurysm repair (EVAR). Nine single-arm, open-label studies were included in pooled metanalysis (6 studies of EVAR patients, 2 studies of thoracic EVAR (TEVAR) patients and 1 study of both EVAR and TEVAR patients).
      Table 1Summary characteristics of 14 included studies of patients with endovascular aortic aneurysm repair (EVAR) or TEVAR and endoanchor fixation
      AuthorYearStudy designRepairEA systemEA fixationGraft
      Deaton et al.
      • Deaton D.H.
      • Mehta M.
      • Kasirajan K.
      • Chaikof E.
      • Farber M.
      • Glickman M.H.
      • et al.
      The phase I multicenter trial (STAPLE-1) of the Aptus endovascular repair system: results at 6 months and 1 year.
      2009Prospective

      Multicentre
      EVARHeli-FXPrimaryAptus
      Mehta et al.
      • Mehta M.
      • Henretta J.
      • Glickman M.
      • Deaton D.
      • Naslund T.C.
      • Gray B.
      • et al.
      Outcome of the pivotal study of the Aptus endovascular abdominal aortic aneurysms repair system.
      2014Prospective

      Multicentre
      EVARHeli-FXPrimaryAptus

      Gore Excluder
      Perdikides et al.
      • Perdikides T.
      • Melas N.
      • Lagios K.
      • Saratzis A.
      • Siafakas A.
      • Bountouris I.
      • et al.
      Primary endoanchoring in the endovascular repair of abdominal aortic aneurysms with an unfavorable neck.
      2012Prospective

      Two centre
      EVARHeli-FXPrimaryEndurant

      Zenith
      Galiñanes et al.
      • Galiñanes E.L.
      • Hernandez E.
      • Krajcer Z.
      Preliminary results of adjunctive use of endoanchors in the treatment of short neck and pararenal abdominal aortic aneurysms.
      2016Retrospective

      Single centre
      EVARHeli-FXPrimaryVarious
      Valdivia et al.
      • Valdivia A.R.
      • Beropoulis E.
      • Pitoulias G.
      • Pratesi G.
      • Alvarez Marcos F.
      • Barbante M.
      • et al.
      Multicenter registry about the use of endoanchors in the endovascular repair of abdominal aortic aneurysms with hostile neck showed successful but delayed endograft sealing within intraoperative type ia endoleak cases.
      2019Prospective

      Multicentre
      EVARHeli-FXPrimaryEndurant

      Incraft
      Giudice et al.
      • Giudice R.
      • Borghese O.
      • Sbenaglia G.
      • Coscarella C.
      • Gregorio C.D.
      • Leopardi M.
      • et al.
      The use of EndoAnchors in endovascular repair of abdominal aortic aneurysms with challenging proximal neck: single-centre experience.
      2019Retrospective

      Single centre
      EVARHeli-FXPrimary

      Secondary
      Endurant

      Talent

      Zenit
      de Vries et al.
      • de Vries J.P.
      • Ouriel K.
      • Mehta M.
      • Varnagy D.
      • Moore W.M.
      • Arko F.R.
      • et al.
      Analysis of EndoAnchors for endovascular aneurysm repair by indications for use.
      2014Prospective

      Multicentre
      EVARHeli-FXPrimary

      Secondary
      Various
      Goudeketting et al.
      • Goudeketting S.R.
      • van Noort K.
      • Ouriel K.
      • Jordan W.D.
      • Panneton J.M.
      • Slump C.H.
      • et al.
      Influence of aortic neck characteristics on successful aortic wall penetration of EndoAnchors in therapeutic use during endovascular aneurysm repair.
      2018Retrospective

      Single centre
      EVARHeli-FXPrimary

      Secondary
      Various
      Avci et al.
      • Avci M.
      • Vos J.A.
      • Kolvenbach R.R.
      • Verhoeven E.L.
      • Perdikides T.
      • Resch T.A.
      • et al.
      The use of endoanchors in repair EVAR cases to improve proximal endograft fixation.
      2012Prospective

      Multicentre
      EVARHeli-FXSecondaryTalent

      Excluder

      AneuRx
      Ho et al.
      • Ho V.T.
      • George E.L.
      • Dua A.
      • Lavingia K.S.
      • Sgroi M.D.
      • Dake M.D.
      • et al.
      Early real-world experience with endoanchors by indication.
      2019Prospective

      Single centre
      EVAR

      TEVAR
      Heli-FXPrimary

      Secondary
      Cook

      Gore

      Medtronic
      Oikonomou et al.
      • Oikonomou K.
      • Kasprzak P.
      • Schierling W.
      • Kopp R.
      • Pfister K.
      Indications for the use of endoanchors: state of the art.
      2018Retrospective

      Single centre
      EVAR

      TEVAR
      Heli-FXPrimary

      Secondary
      Medtronic

      Gore

      Cook
      Kasprzak et al.
      • Kasprzak P.
      • Pfister K.
      • Janotta M.
      • Kopp R.
      EndoAnchor placement in thoracic and thoracoabdominal stent-grafts to repair complications of nonalignment.
      2013Prospective

      Single centre
      TEVARHeli-FXPrimary

      Secondary
      Gore

      Cook
      Ongstad et al.
      • Ongstad S.B.
      • Miller D.F.
      • Panneton J.M.
      The use of EndoAnchors to rescue complicated TEVAR procedures.
      2016Retrospective

      Single centre
      TEVARHeli-FXPrimary

      Secondary
      Various
      Donas et al.
      • Donas K.P.
      • Torsello G.
      Midterm results of the Anson Refix endostapling fixation system for aortic stent-grafts.
      2010Prospective

      Single centre
      EVARAnson RefixPrimaryTalent

      Zenith
      EA = endoanchor; EVAR = endovascular abdominal aortic repair; TEVAR = thoracic endovascular aortic repair.

      Data extraction

      Data were extracted on patient numbers and demographics, aneurysm neck characteristics, endograft type, and number of endoanchors deployed. Outcomes of interest were technical success in endoanchor deployment, number of patients with TIaE and graft migration, aneurysm related re-intervention, re-intervention for endoanchor failure, endoanchor adverse events, and all cause 30 day mortality.

      Study selection for meta-analysis

      Identified studies were scrutinised in terms of publication authors, study institution, recruitment period, and publication date to prevent inclusion of duplicate data. Inter-study heterogeneity required judgement regarding which studies to include in meta-analysis (rationales are detailed below). Seven EVAR
      • Deaton D.H.
      • Mehta M.
      • Kasirajan K.
      • Chaikof E.
      • Farber M.
      • Glickman M.H.
      • et al.
      The phase I multicenter trial (STAPLE-1) of the Aptus endovascular repair system: results at 6 months and 1 year.
      ,
      • Mehta M.
      • Henretta J.
      • Glickman M.
      • Deaton D.
      • Naslund T.C.
      • Gray B.
      • et al.
      Outcome of the pivotal study of the Aptus endovascular abdominal aortic aneurysms repair system.
      ,
      • Galiñanes E.L.
      • Hernandez E.
      • Krajcer Z.
      Preliminary results of adjunctive use of endoanchors in the treatment of short neck and pararenal abdominal aortic aneurysms.
      ,
      • Giudice R.
      • Borghese O.
      • Sbenaglia G.
      • Coscarella C.
      • Gregorio C.D.
      • Leopardi M.
      • et al.
      The use of EndoAnchors in endovascular repair of abdominal aortic aneurysms with challenging proximal neck: single-centre experience.
      ,
      • de Vries J.P.
      • Ouriel K.
      • Mehta M.
      • Varnagy D.
      • Moore W.M.
      • Arko F.R.
      • et al.
      Analysis of EndoAnchors for endovascular aneurysm repair by indications for use.
      ,
      • Ho V.T.
      • George E.L.
      • Dua A.
      • Lavingia K.S.
      • Sgroi M.D.
      • Dake M.D.
      • et al.
      Early real-world experience with endoanchors by indication.
      ,
      • Avci M.
      • Vos J.A.
      • Kolvenbach R.R.
      • Verhoeven E.L.
      • Perdikides T.
      • Resch T.A.
      • et al.
      The use of endoanchors in repair EVAR cases to improve proximal endograft fixation.
      and three TEVAR studies
      • Ho V.T.
      • George E.L.
      • Dua A.
      • Lavingia K.S.
      • Sgroi M.D.
      • Dake M.D.
      • et al.
      Early real-world experience with endoanchors by indication.
      ,
      • Kasprzak P.
      • Pfister K.
      • Janotta M.
      • Kopp R.
      EndoAnchor placement in thoracic and thoracoabdominal stent-grafts to repair complications of nonalignment.
      ,
      • Ongstad S.B.
      • Miller D.F.
      • Panneton J.M.
      The use of EndoAnchors to rescue complicated TEVAR procedures.
      were included in the meta-analysis.
      Because of the numerous ANCHOR trial publications, baseline and follow up data from the Jordan et al.
      • Jordan W.D.
      • Mehta M.
      • Varnagy D.
      • Moore W.M.
      • Arko F.R.
      • Joye J.
      • et al.
      Results of the ANCHOR prospective, multicenter registry of EndoAnchors for type Ia endoleaks and endograft migration in patients with challenging anatomy.
      and de Vries et al.
      • de Vries J.P.
      • Ouriel K.
      • Mehta M.
      • Varnagy D.
      • Moore W.M.
      • Arko F.R.
      • et al.
      Analysis of EndoAnchors for endovascular aneurysm repair by indications for use.
      studies were used, respectively, for EVAR meta-analysis.
      In the studies by Perdikides et al.
      • Perdikides T.
      • Melas N.
      • Lagios K.
      • Saratzis A.
      • Siafakas A.
      • Bountouris I.
      • et al.
      Primary endoanchoring in the endovascular repair of abdominal aortic aneurysms with an unfavorable neck.
      and Valdivia et al.,
      • Valdivia A.R.
      • Beropoulis E.
      • Pitoulias G.
      • Pratesi G.
      • Alvarez Marcos F.
      • Barbante M.
      • et al.
      Multicenter registry about the use of endoanchors in the endovascular repair of abdominal aortic aneurysms with hostile neck showed successful but delayed endograft sealing within intraoperative type ia endoleak cases.
      recruitment centres were also study locations in the ANCHOR trial. Both studies were excluded from EVAR meta-analysis.
      In the study by Goudeketting et al.,
      • Goudeketting S.R.
      • van Noort K.
      • Ouriel K.
      • Jordan W.D.
      • Panneton J.M.
      • Slump C.H.
      • et al.
      Influence of aortic neck characteristics on successful aortic wall penetration of EndoAnchors in therapeutic use during endovascular aneurysm repair.
      outcomes of EVAR patients undergoing primary and secondary fixation could not be distinguished. This study was excluded from EVAR meta-analysis.
      In the study by Oikonomou et al.,
      • Oikonomou K.
      • Kasprzak P.
      • Schierling W.
      • Kopp R.
      • Pfister K.
      Indications for the use of endoanchors: state of the art.
      the length of follow up was 30 days, with potential patient overlap with the Kasprzak et al. study.
      • Kasprzak P.
      • Pfister K.
      • Janotta M.
      • Kopp R.
      EndoAnchor placement in thoracic and thoracoabdominal stent-grafts to repair complications of nonalignment.
      The former study was excluded from EVAR and TEVAR meta-analysis.
      The study by Donas et al.
      • Donas K.P.
      • Torsello G.
      Midterm results of the Anson Refix endostapling fixation system for aortic stent-grafts.
      used the Anson Refix Endostapler device (Lombard Medical Technologies, Didcot, UK) which is no longer commercially available. This study was excluded.
      TEVAR meta-analysis is combined for primary and secondary patients as outcomes were not consistently distinguished between these two subgroups. Endoanchor related complications are presented descriptively as adverse events were rare.

      Statistical analysis

      Raw data were processed in Microsoft Excel (Microsoft Corporation, WA, USA). Meta-analysis was conducted using OpenMeta[Analyst] (Brown University, RI, USA) and MedCalc Statistical Software version 19.1 (MedCalc Software bv, Ostend, Belgium).
      For continuous variables, a weighted mean ± 95% confidence interval (CI) was calculated using a continuous random effects model (DerSimonian-Laird method, 1986). When mean ± standard deviation were not provided, these were estimated from the median, range, and sample size.
      • Hozo S.P.
      • Djulbegovic B.
      • Hozo I.
      Estimating the mean and variance from the median, range, and the size of a sample.
      For dichotomous variables, a meta-analysis of proportion was used to calculate the weighted summary proportion using the Freeman-Tukey transformation (arcsine square root; Freeman and Tukey, 1950) under a random effects model (DerSimonian-Laird method, 1986). Heterogeneity was assessed using I2.

      Results

      EVAR with primary fixation

      Four hundred and fifty-five patients underwent endoanchor implantation during the primary EVAR procedure (Table 2). Weighted mean age was 73.8 years (95% CI 72.6–75.0; I2 47.9%; p = .15). The proportion of males was 84.7% (95% CI 71.1–94.5; I2 87.9%, p < .001). A total of 288 patients was available at a mean follow up of 15.4 months (95% CI 1.8–29.0; I2 100%; p < .001). Studies used computed tomography (CT) as well as abdominal radiography
      • Deaton D.H.
      • Mehta M.
      • Kasirajan K.
      • Chaikof E.
      • Farber M.
      • Glickman M.H.
      • et al.
      The phase I multicenter trial (STAPLE-1) of the Aptus endovascular repair system: results at 6 months and 1 year.
      and duplex sonography
      • de Vries J.P.
      • Ouriel K.
      • Mehta M.
      • Varnagy D.
      • Moore W.M.
      • Arko F.R.
      • et al.
      Analysis of EndoAnchors for endovascular aneurysm repair by indications for use.
      at follow up. Indication for endoanchors included prophylaxis against endoleak or graft migration (n = 381), treatment of intra-operative endoleak (n = 70), and intra-operative distal graft maldeployment alongside aortic cuff extension to achieve an adequate sealing zone (n = 4). A proportion of patients underwent adjunctive proximal procedures alongside endoanchors (Table 2). Patient aneurysm characteristics included an aortic neck diameter of 25.2 mm (95% CI 22.9–27.5; I2 98.0%; p < .001), neck length of 15.4 mm (95% CI 7.8–23.0; I2 98.9%; p < .001), and neck angulation of 27.6° (95% CI 22.2–33.1; I2 91.6%; p < .001).
      Table 2Baseline characteristics and follow up clinical outcomes of patients with endovascular aortic aneurysm repair (EVAR) and endoanchor fixation per included study
      StudyNo. of patients (primary, secondary)EA indication n (%)Mean no. of EAAdjunctsTS n (%)Comp. TIaE n (%)FU TIaE n (%)M n (%)EA adverse eventsMean FU period, months
      Deaton et al.
      • Deaton D.H.
      • Mehta M.
      • Kasirajan K.
      • Chaikof E.
      • Farber M.
      • Glickman M.H.
      • et al.
      The phase I multicenter trial (STAPLE-1) of the Aptus endovascular repair system: results at 6 months and 1 year.
      21 (21, 0)PPX 21 (100)4.62 cuffs

      1 stent
      21 (100)000012
      No. of patients at follow up was less than baseline in Deaton et al. n = 14 (66.7%), Mehta et al. n = 78 (50.3%), and de Vries et al. n = 202 (63.3%). Median follow up period is stated for the Perdikides et al., Giudice et al., and Goudeketting et al. studies. De Vries et al.: Imaging follow up stated as 7 months and clinical follow up stated as 16 months.
      Mehta et al.
      • Mehta M.
      • Henretta J.
      • Glickman M.
      • Deaton D.
      • Naslund T.C.
      • Gray B.
      • et al.
      Outcome of the pivotal study of the Aptus endovascular abdominal aortic aneurysms repair system.
      155
      Two (of 155) endograft delivery failure: one failure to cannulate contralateral gate and open conversion, one misdeployment of endograft. EA implanted in total 154 patients.
      (155, 0)
      PPX 155 (100)5.37 cuffs154 (100)01 (1.3)5 (6.4)036
      No. of patients at follow up was less than baseline in Deaton et al. n = 14 (66.7%), Mehta et al. n = 78 (50.3%), and de Vries et al. n = 202 (63.3%). Median follow up period is stated for the Perdikides et al., Giudice et al., and Goudeketting et al. studies. De Vries et al.: Imaging follow up stated as 7 months and clinical follow up stated as 16 months.
      Perdikides et al.
      • Perdikides T.
      • Melas N.
      • Lagios K.
      • Saratzis A.
      • Siafakas A.
      • Bountouris I.
      • et al.
      Primary endoanchoring in the endovascular repair of abdominal aortic aneurysms with an unfavorable neck.
      Studies excluded from pooled meta-analysis, as outlined in the Study selection for meta-analysis subsection.
      13 (13, 0)PPX 13 (100)4
      Perdikides et al.: Median no. of endoanchors stated. Ho et al.: No. of endoanchors for primary and secondary patients only available separately. Oikonomou et al.: Range no. of deployed endoanchors stated. de Vries et al.: No. of endoanchors in primary and secondary patients was 5.5 and 6.8, respectively. Donas et al.: Technical success only stated as proportion of total deployed endoanchors; 20 of 29 (69%) endoanchors were successfully deployed.
      1 cuff13 (100)2 (15.4)0007
      No. of patients at follow up was less than baseline in Deaton et al. n = 14 (66.7%), Mehta et al. n = 78 (50.3%), and de Vries et al. n = 202 (63.3%). Median follow up period is stated for the Perdikides et al., Giudice et al., and Goudeketting et al. studies. De Vries et al.: Imaging follow up stated as 7 months and clinical follow up stated as 16 months.
      Galiñanes et al.
      • Galiñanes E.L.
      • Hernandez E.
      • Krajcer Z.
      Preliminary results of adjunctive use of endoanchors in the treatment of short neck and pararenal abdominal aortic aneurysms.
      9 (9,0)PPX 9 (100)8.25 chimneys

      4 cuffs
      9 (100)00008
      Valdivia et al.
      • Valdivia A.R.
      • Beropoulis E.
      • Pitoulias G.
      • Pratesi G.
      • Alvarez Marcos F.
      • Barbante M.
      • et al.
      Multicenter registry about the use of endoanchors in the endovascular repair of abdominal aortic aneurysms with hostile neck showed successful but delayed endograft sealing within intraoperative type ia endoleak cases.
      Studies excluded from pooled meta-analysis, as outlined in the Study selection for meta-analysis subsection.
      46 (46, 0)PPX 24 (52.2)

      Intra-op TIaE 22 (47.8)
      62 renal stents45 (97.8)9 (19.6)001 mal-positioned EA15
      Giudice et al.
      • Giudice R.
      • Borghese O.
      • Sbenaglia G.
      • Coscarella C.
      • Gregorio C.D.
      • Leopardi M.
      • et al.
      The use of EndoAnchors in endovascular repair of abdominal aortic aneurysms with challenging proximal neck: single-centre experience.
      17 (9,8)PPX 9 (52.9)

      TIaE/M 8 (47.1)
      56 cuffs17 (100)000013
      No. of patients at follow up was less than baseline in Deaton et al. n = 14 (66.7%), Mehta et al. n = 78 (50.3%), and de Vries et al. n = 202 (63.3%). Median follow up period is stated for the Perdikides et al., Giudice et al., and Goudeketting et al. studies. De Vries et al.: Imaging follow up stated as 7 months and clinical follow up stated as 16 months.
      de Vries et al.
      • de Vries J.P.
      • Ouriel K.
      • Mehta M.
      • Varnagy D.
      • Moore W.M.
      • Arko F.R.
      • et al.
      Analysis of EndoAnchors for endovascular aneurysm repair by indications for use.
      319 (242, 77)PPX 178 (55.8)

      Intra-op TIaE 60 (18.8)

      Maldeployed graft 4 (1.3)

      TIaE 45 (14.1)

      M 11 (3.4)

      TIaE + M 21 (6.6)
      5.8
      Perdikides et al.: Median no. of endoanchors stated. Ho et al.: No. of endoanchors for primary and secondary patients only available separately. Oikonomou et al.: Range no. of deployed endoanchors stated. de Vries et al.: No. of endoanchors in primary and secondary patients was 5.5 and 6.8, respectively. Donas et al.: Technical success only stated as proportion of total deployed endoanchors; 20 of 29 (69%) endoanchors were successfully deployed.
      74 cuffs

      7 bare stents
      303 (95)
      de Vries et al.: Technical success in primary and secondary patients was 96.3 and 90.9%, respectively. Avci et al.: Technical success is less than reported by authors; one EA dislodged classified as technical failure here.
      28 (8.8)
      de Vries et al.: Completion TIaE occurred in 18 (7.4%) primary patients and 10 (13%) secondary patients. Follow up TIaE occurred in 8/158 (5.1%) primary patients and 11/44 (25%) secondary patients. Ho et al.: Completion and follow up TIaE only occurred in secondary patients at a rate of 6 (54.5%) and 5 (45.5%), respectively.
      19 (9.4)
      de Vries et al.: Completion TIaE occurred in 18 (7.4%) primary patients and 10 (13%) secondary patients. Follow up TIaE occurred in 8/158 (5.1%) primary patients and 11/44 (25%) secondary patients. Ho et al.: Completion and follow up TIaE only occurred in secondary patients at a rate of 6 (54.5%) and 5 (45.5%), respectively.
      02 EA fracture

      1 entrapped EA
      7
      No. of patients at follow up was less than baseline in Deaton et al. n = 14 (66.7%), Mehta et al. n = 78 (50.3%), and de Vries et al. n = 202 (63.3%). Median follow up period is stated for the Perdikides et al., Giudice et al., and Goudeketting et al. studies. De Vries et al.: Imaging follow up stated as 7 months and clinical follow up stated as 16 months.
      Avci et al.
      • Avci M.
      • Vos J.A.
      • Kolvenbach R.R.
      • Verhoeven E.L.
      • Perdikides T.
      • Resch T.A.
      • et al.
      The use of endoanchors in repair EVAR cases to improve proximal endograft fixation.
      11 (0, 11)TIaE 4 (36.4)

      M 1 (9.1)

      TIaE + M 6 (54.5)
      6.38 cuffs10 (90.1)
      de Vries et al.: Technical success in primary and secondary patients was 96.3 and 90.9%, respectively. Avci et al.: Technical success is less than reported by authors; one EA dislodged classified as technical failure here.
      2 (18.2)2 (18.2)01 dislocated EA10
      Ho et al.
      • Ho V.T.
      • George E.L.
      • Dua A.
      • Lavingia K.S.
      • Sgroi M.D.
      • Dake M.D.
      • et al.
      Early real-world experience with endoanchors by indication.
      31 (20, 11)PPX 10 (32.3)

      Intra-op TIaE 10 (32.3)

      TIaE 11 (35.5)
      9.1,

      10
      Perdikides et al.: Median no. of endoanchors stated. Ho et al.: No. of endoanchors for primary and secondary patients only available separately. Oikonomou et al.: Range no. of deployed endoanchors stated. de Vries et al.: No. of endoanchors in primary and secondary patients was 5.5 and 6.8, respectively. Donas et al.: Technical success only stated as proportion of total deployed endoanchors; 20 of 29 (69%) endoanchors were successfully deployed.
      31 (100)6 (19.4)
      de Vries et al.: Completion TIaE occurred in 18 (7.4%) primary patients and 10 (13%) secondary patients. Follow up TIaE occurred in 8/158 (5.1%) primary patients and 11/44 (25%) secondary patients. Ho et al.: Completion and follow up TIaE only occurred in secondary patients at a rate of 6 (54.5%) and 5 (45.5%), respectively.
      5 (16.1)
      de Vries et al.: Completion TIaE occurred in 18 (7.4%) primary patients and 10 (13%) secondary patients. Follow up TIaE occurred in 8/158 (5.1%) primary patients and 11/44 (25%) secondary patients. Ho et al.: Completion and follow up TIaE only occurred in secondary patients at a rate of 6 (54.5%) and 5 (45.5%), respectively.
      01 CIA dissection11.9
      Goudeketting et al.
      • Goudeketting S.R.
      • van Noort K.
      • Ouriel K.
      • Jordan W.D.
      • Panneton J.M.
      • Slump C.H.
      • et al.
      Influence of aortic neck characteristics on successful aortic wall penetration of EndoAnchors in therapeutic use during endovascular aneurysm repair.
      Studies excluded from pooled meta-analysis, as outlined in the Study selection for meta-analysis subsection.
      51 (38, 13)PPX 31 (60.8)

      TIaE/M 20 (39.2)
      6.73 stents

      8 chimneys

      16 cuffs
      49 (96.1)10 (19.6)6 (11.8)01 EA fracture 2 dislocated EA24
      No. of patients at follow up was less than baseline in Deaton et al. n = 14 (66.7%), Mehta et al. n = 78 (50.3%), and de Vries et al. n = 202 (63.3%). Median follow up period is stated for the Perdikides et al., Giudice et al., and Goudeketting et al. studies. De Vries et al.: Imaging follow up stated as 7 months and clinical follow up stated as 16 months.
      Oikonomou et al.
      • Oikonomou K.
      • Kasprzak P.
      • Schierling W.
      • Kopp R.
      • Pfister K.
      Indications for the use of endoanchors: state of the art.
      Studies excluded from pooled meta-analysis, as outlined in the Study selection for meta-analysis subsection.
      82 (66, 16)PPX 71 (71)
      Indication for EA is reported combined for EVAR and TEVAR patients.


      Intra-op TIaE 8 (8)

      Intra-op M 1 (1)

      TIaE 13 (13)

      M 4 (4)

      Graft protrusion 3 (3)
      4–8
      Perdikides et al.: Median no. of endoanchors stated. Ho et al.: No. of endoanchors for primary and secondary patients only available separately. Oikonomou et al.: Range no. of deployed endoanchors stated. de Vries et al.: No. of endoanchors in primary and secondary patients was 5.5 and 6.8, respectively. Donas et al.: Technical success only stated as proportion of total deployed endoanchors; 20 of 29 (69%) endoanchors were successfully deployed.
      9 proximal extension82 (100)N/A0001
      Donas et al.
      • Donas K.P.
      • Torsello G.
      Midterm results of the Anson Refix endostapling fixation system for aortic stent-grafts.
      Studies excluded from pooled meta-analysis, as outlined in the Study selection for meta-analysis subsection.
      8 (8, 0)PPX 8 (100)3.620 (69)
      Perdikides et al.: Median no. of endoanchors stated. Ho et al.: No. of endoanchors for primary and secondary patients only available separately. Oikonomou et al.: Range no. of deployed endoanchors stated. de Vries et al.: No. of endoanchors in primary and secondary patients was 5.5 and 6.8, respectively. Donas et al.: Technical success only stated as proportion of total deployed endoanchors; 20 of 29 (69%) endoanchors were successfully deployed.
      000018
      CIA = common iliac artery; Comp. = completion angiogram post endoanchor deployment; EA = endoanchor; EL = endoleak; FU = follow up; intra-op = intra-operative; M = migration; PPX = prophylaxis; TS = technical success; TIaE = Type Ia endoleak.
      Studies excluded from pooled meta-analysis, as outlined in the Study selection for meta-analysis subsection.
      Two (of 155) endograft delivery failure: one failure to cannulate contralateral gate and open conversion, one misdeployment of endograft. EA implanted in total 154 patients.
      Indication for EA is reported combined for EVAR and TEVAR patients.
      § Perdikides et al.: Median no. of endoanchors stated. Ho et al.: No. of endoanchors for primary and secondary patients only available separately. Oikonomou et al.: Range no. of deployed endoanchors stated. de Vries et al.: No. of endoanchors in primary and secondary patients was 5.5 and 6.8, respectively. Donas et al.: Technical success only stated as proportion of total deployed endoanchors; 20 of 29 (69%) endoanchors were successfully deployed.
      || de Vries et al.: Technical success in primary and secondary patients was 96.3 and 90.9%, respectively. Avci et al.: Technical success is less than reported by authors; one EA dislodged classified as technical failure here.
      de Vries et al.: Completion TIaE occurred in 18 (7.4%) primary patients and 10 (13%) secondary patients. Follow up TIaE occurred in 8/158 (5.1%) primary patients and 11/44 (25%) secondary patients. Ho et al.: Completion and follow up TIaE only occurred in secondary patients at a rate of 6 (54.5%) and 5 (45.5%), respectively.
      # No. of patients at follow up was less than baseline in Deaton et al. n = 14 (66.7%), Mehta et al. n = 78 (50.3%), and de Vries et al. n = 202 (63.3%). Median follow up period is stated for the Perdikides et al., Giudice et al., and Goudeketting et al. studies. De Vries et al.: Imaging follow up stated as 7 months and clinical follow up stated as 16 months.
      A mean of 5.5 (95% CI 5.0–6.1; I2 82.3%; p < .001) endoanchors were deployed per patient. Mean total procedure time was 136.5 min (95% CI 130.1–142.9; I2 0%; p = .90), with mean endostapling time of 18.0 min (95% CI 16.1–20.0; I2 47.5; p = .13). Technical success was 98.4% (95% CI 95.7–99.8; I2 48.6%; p = .080). The TIaE rate on completion angiography was 2.1% (95% CI 0.034–7.2; I2 77.9%; p < .001). The rate of TIaE at follow up was 3.5% (95% CI 1.7–5.9; I2 0%; p = .70). The rate of graft migration at follow up was 2.0% (95% CI 0.12–6.0; I2 54.8%; p = .051) (Fig. 2). Outcomes for TIaE and migration by indication for use are described in Table 3.
      Figure 2
      Figure 2Forest plots of pooled rate of (A) type Ia endoleak and (B) graft migration in patients who underwent endovascular aortic aneurysm repair and primary endoanchor fixation. The weighted proportion of type Ia endoleak was 3.5% (95% CI 1.7–5.9) and graft migration was 2.0% (95% CI 0.12–6.0) after a mean follow up of 15.4 months.
      Table 3Weighted meta-analysis of proportions for rate of Type Ia endoleak and graft migration in patients with endovascular aortic aneurysm repair (EVAR) and endoanchor fixation by indication for endoanchor use
      Indication for EAPatientsTechnical success – %Follow up period – monthsPatients completed follow upFollow up TIaE – %Follow up graft migration – %
      Primary fixation45598.4 (95.7–99.8)15.4 (1.8–29.0)288 (63.3)3.5 (1.7–5.9)2.0 (0.12–6.0)
       Prophylaxis381 (83.7)233 (59.1)2.8 (1.1–5.3)2.2 (0.22–6.3)
       Intra-operative TIaE70 (15.4)51 (72.8)8.2 (1.9–18.2)0
       Graft maldeployment4 (0.88)4 (100)00
      Secondary fixation10791.8 (86.1–96.2)10.7 (7.8–13.6)74 (69.2)22.6 (9.1–40.0)0
       TIaE alone60 (56.1)44 (73.3)39.3 (26.0–53.5)0
       Graft migration12 (11.2)7 (58.3)00
       TIaE and/or graft migration35 (32.7)23 (65.7)6.6 (0.5–19.3)0
      Data are given as n (%) or as weighted mean (95% confidence interval). EA = endoanchor; TIaE = Type Ia endoleak.
      There were 136 aneurysm related re-interventions in the primary group, of which 122 (89.7%) re-interventions were performed in 74 patients in a single study.
      • Mehta M.
      • Henretta J.
      • Glickman M.
      • Deaton D.
      • Naslund T.C.
      • Gray B.
      • et al.
      Outcome of the pivotal study of the Aptus endovascular abdominal aortic aneurysms repair system.
      There were three re-interventions for endoanchor failure.
      In a reported 196 primary EVAR patients, aneurysm sac diameter decreased by > 5 mm in 55.3% (95% CI 41.3–69.0; I2 65.1%; p = .057) of patients. There was no change in 43.5% (95% CI 29.5–58.9; I2 69.1%; p = .040) of patients, while sac diameter increased by > 5 mm in 1.4% (95% CI 0.25–3.5; I2 0%; p = .70) of patients post endoanchor fixation.

      EVAR with secondary fixation

      One hundred and seven patients who underwent endoanchor fixation as a secondary procedure were included in the meta-analysis. The weighted mean age was 77.4 years (95% CI 75.9–78.8; I2 0%; p = .86). The proportion of males was 74.1% (95% CI 65.2–82.1; I2 0%; p = .93). Seventy-four patients were available at a mean follow up of 10.7 months (95% CI 7.8–13.6; I2 88.3%; p < .001). The indication for secondary fixation included endoleak alone (n = 60), migration alone (n = 12), and endoleak and/or migration (n = 35). Patient aneurysm characteristics included an aortic neck diameter of 28.3 mm (95% CI 28.3–30.2; I2 0%; p = .37) and neck length of 13.4 mm (95% CI 10.8–16.1; I2 64.5; p = .093).
      A mean of 6.1 (95% CI 5.1–7.1; I2 77.3%; p = .01) endoanchors was deployed per patient. Technical success was 91.8% (95% CI 86.1–96.2; I2 0%; p = .60). Rates of TIaE at completion and follow up were 19.7% (95% CI 5.3–40.3; I2 72.6%; p = .010) and 22.6% (95% CI 9.1–40.0; I2 56.7%; p = .070), respectively (Fig. 3a ). There were no graft migrations. Outcomes for TIaE by indication for use are provided in Table 3. There were 13 aneurysm related re-interventions and eight re-interventions for endoanchor failure.
      Figure 3
      Figure 3Forest plots of pooled rate of Type Ia endoleak (TIaE) in (A) patients who underwent endovascular aortic aneurysm repair followed by secondary endoanchor fixation and (B) patients who underwent thoracic endovascular aortic aneurysm repair (TEVAR) with endoanchor fixation. The weighted proportion of type Ia endoleak in secondary endovascular aortic aneurysm repair was 22.6% (95% CI 9.1–40.0) after a mean follow up of 10.7 months. The weighted proportion of type Ia endoleak in TEVAR was 8.7% (95% CI 1.0–18.9) after a mean follow up of 9.8 months.
      In the entire EVAR cohort, there were three endoanchor fractures, three dislocated endoanchors, and one entrapped endoanchor requiring snare retrieval. There was one common iliac artery dissection caused by wire manipulation requiring a covered stent. All cause 30 day mortality was 0.82% (95% CI 0.20–1.85; I2 0%; p = .98).

      TEVAR

      A total of 66 TEVAR patients underwent endoanchor fixation (29 primary, 31 secondary, six indeterminate). The weighted mean age was 68.5 years (95% CI 65.7–71.3; I2 0%; p = .42), and the proportion of males was 64.5% (95% CI 52.9–75.3; I2 0%; p = 1.0). The mean number of endoanchors deployed was 7.1 (95% CI 2.5–11.7; I2 97.6%; p < .001). Along with proximal fixation, endoanchors were deployed distally in all studies and near branch vessel segments in one study
      • Ongstad S.B.
      • Miller D.F.
      • Panneton J.M.
      The use of EndoAnchors to rescue complicated TEVAR procedures.
      to treat other types of endoleaks and graft infolding. The weighted mean follow up was 9.8 months (95% CI 8.1–11.5; I2 0%; p = .80) (Table 4). Studies used CT at follow up as well as abdominal radiography and duplex sonography in one study.
      • Kasprzak P.
      • Pfister K.
      • Janotta M.
      • Kopp R.
      EndoAnchor placement in thoracic and thoracoabdominal stent-grafts to repair complications of nonalignment.
      Table 4Baseline characteristics and clinical outcomes at follow up in patients with TEVAR and endoanchor fixation per included study
      StudyNo. of patients (primary, secondary)EA indication n (%)Mean no. of EAAdjunctsTSComp. TIaEFU TIaEMEA adverse eventsMean FU period – months
      Ho et al.
      • Ho V.T.
      • George E.L.
      • Dua A.
      • Lavingia K.S.
      • Sgroi M.D.
      • Dake M.D.
      • et al.
      Early real-world experience with endoanchors by indication.
      6
      Number of primary and secondary patients not available.
      PPX
      Ho et al.: Number of patients per EA indication not available. Oikonomou et al.: Indication for EA is reported combined for EVAR and TEVAR patients, please refer to Table 2.


      Intra-op EL

      EL
      8.35 (83.3)2 (33.3)2 (33.3)01 misdeployed EA, aortic dissection, death9.4
      Oikonomou et al.
      • Oikonomou K.
      • Kasprzak P.
      • Schierling W.
      • Kopp R.
      • Pfister K.
      Indications for the use of endoanchors: state of the art.
      Studies excluded from pooled meta-analysis, as outlined in the Study selection for meta-analysis subsection.
      18 (10, 8)N/A4–8
      Range no. of deployed EAs stated.
      5 proximal extensions18 (100)N/A1 (5.6)001
      Kasprzak et al.
      • Kasprzak P.
      • Pfister K.
      • Janotta M.
      • Kopp R.
      EndoAnchor placement in thoracic and thoracoabdominal stent-grafts to repair complications of nonalignment.
      6 (2, 4)TIaE 1 (16.7)

      M 1 (16.7)

      TIaE + M 1 (16.7)

      Ib EL 2 (33.3)

      Graft infolding 1 (16.7)
      4.723 (82.1)
      Technical success is less than reported by authors. Five EAs required reapplication during the same procedure. Technical success stated as proportion of total deployed EAs; 23 of 28 (82.1%) EAs were successfully deployed.
      000011
      Ongstad et al.
      • Ongstad S.B.
      • Miller D.F.
      • Panneton J.M.
      The use of EndoAnchors to rescue complicated TEVAR procedures.
      54 (27, 27)PPX 37 (68.5)

      Intra-op/FU EL 17 (31.5)
      9.4Fenestrated/chimney grafts53 (98.2)N/A1 (1.9)01 misdeployed EA9.6
      Outcomes data are given as n (%). Comp. = completion angiogram post endoanchor deployment; EA = endoanchor; EL = endoleak; FU = follow up; intra-op = intra-operative; M = migration; PPX = prophylaxis; TS = technical success; TIaE = Type Ia endoleak.
      Studies excluded from pooled meta-analysis, as outlined in the Study selection for meta-analysis subsection.
      Number of primary and secondary patients not available.
      Ho et al.: Number of patients per EA indication not available. Oikonomou et al.: Indication for EA is reported combined for EVAR and TEVAR patients, please refer to Table 2.
      § Range no. of deployed EAs stated.
      || Technical success is less than reported by authors. Five EAs required reapplication during the same procedure. Technical success stated as proportion of total deployed EAs; 23 of 28 (82.1%) EAs were successfully deployed.
      Technical success in endoanchor deployment was 90.3% (95% CI 72.1–99.4, I2 54.0%; p = .11). The overall rate of TIaE was 8.7% (95% CI 1.0–18.9%; I2 64.4%; p = .060) at follow up (Fig. 3b). Specifically, there were no endoleaks in the 29 patients with primary fixation, one endoleak in the 31 secondary fixation patients, and two endoleaks in six indeterminate patients. There were no graft migrations. There were nine reported aneurysm related re-interventions and one endoanchor related re-intervention.
      Endoanchor related adverse events included two maldeployed endoanchors. In one patient, the endoanchor was irretrievable resulting in a retrograde type A aortic dissection and death. The weighted all cause 30 day mortality was 11.9% (95% CI 5.4–20.6; I2 0%; p = .59). No other death was directly attributed to endoanchor use (two respiratory failure, one ruptured thoracic aneurysm from undiagnosed endoleak, one intracranial haemorrhage, one ruptured iliac artery aneurysm, and one multiple visceral/cerebral infarctions).

      Discussion

      The available evidence for use of endoanchors has been reviewed, both during the primary index procedure and for the treatment of complications during secondary procedures.
      Prevention of TIaE is the key indication for using endoanchors. In patients where endoanchors were used during the primary EVAR procedure, the rate of TIaE was 3.5% at a mean follow up of 15.4 months. In comparison, pooled data from the EVAR-1, DREAM, OVER, and ACE trials report an overall TIaE rate of 4.3%,
      • Powell J.T.
      • Sweeting M.J.
      • Ulug P.
      • Blankensteijn J.D.
      • Lederle F.A.
      • Becquemin J.P.
      • et al.
      Meta-analysis of individual-patient data from EVAR-1, DREAM, OVER and ACE trials comparing outcomes of endovascular or open repair for abdominal aortic aneurysm over 5 years.
      whereas more recently published five year follow up from the GREAT and ENGAGE registeries report a TIaE rate of 2.7% and 4.8%, respectively.
      • Howard D.P.J.
      • Marron C.D.
      • Sideso E.
      • Puckridge P.J.
      • Verhoeven E.L.G.
      • Spark J.I.
      • et al.
      Editor's Choice - 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).
      ,
      • Teijink J.A.W.
      • Power A.H.
      • Böckler D.
      • Peeters P.
      • van Sterkenburg S.
      • Bouwman L.H.
      • et al.
      Editor's Choice - five year outcomes of the endurant stent graft for endovascular abdominal aortic aneurysm repair in the ENGAGE Registry.
      The only relatively comparable controlled data are from a retrospective propensity matched control study from the ANCHOR registry which failed to demonstrate a significant difference in the rate of TIaE between endoanchored and non-endoanchored patients.
      • Muhs B.E.
      • Jordan W.
      • Ouriel K.
      • Rajaee S.
      • de Vries J.P.
      Matched cohort comparison of endovascular abdominal aortic aneurysm repair with and without EndoAnchors.
      The main interest in endoanchors, however, is in patients with challenging aortic neck anatomy, in whom TIaE rates may reach as high as 10%.
      • Antoniou G.A.
      • Georgiadis G.S.
      • Antoniou S.A.
      • Kuhan G.
      • Murray D.
      A meta-analysis of outcomes of endovascular abdominal aortic aneurysm repair in patients with hostile and friendly neck anatomy.
      In this review, weighted neck characteristics in primary EVAR were relatively favourable and did not meet the criteria for neck hostility described in the literature.
      • Aburahma A.F.
      • Campbell J.E.
      • Mousa A.Y.
      • Hass S.M.
      • Stone P.A.
      • Jain A.
      • et al.
      Clinical outcomes for hostile versus favorable aortic neck anatomy in endovascular aortic aneurysm repair using modular devices.
      ,
      • Jordan W.D.
      • de Vries J.P.
      • Ouriel K.
      • Mehta M.
      • Varnagy D.
      • Moore W.M.
      • et al.
      Midterm outcome of EndoAnchors for the prevention of endoleak and stent-graft migration in patients with challenging proximal aortic neck anatomy.
      However, a subgroup analysis of the ANCHOR registry has shown promising outcomes, with the rate of TIaE as low as 1.5% in patients with a challenging proximal neck.
      • Jordan W.D.
      • de Vries J.P.
      • Ouriel K.
      • Mehta M.
      • Varnagy D.
      • Moore W.M.
      • et al.
      Midterm outcome of EndoAnchors for the prevention of endoleak and stent-graft migration in patients with challenging proximal aortic neck anatomy.
      Preventing graft migration is the second main indication for endoanchors. In this review, the rate of graft migration in the primary endoanchored EVAR group was 2.0%. In comparison, the rate of graft migration in the ENGAGE registry was 0.3% at five year follow up.
      • Teijink J.A.W.
      • Power A.H.
      • Böckler D.
      • Peeters P.
      • van Sterkenburg S.
      • Bouwman L.H.
      • et al.
      Editor's Choice - five year outcomes of the endurant stent graft for endovascular abdominal aortic aneurysm repair in the ENGAGE Registry.
      This is lower than results from earlier EVAR literature with rates of 2.9–4.0%, which may in part be attributed to improvements in stent graft technology.
      • Brewster D.C.
      • Jones J.E.
      • Chung T.K.
      • Lamuraglia G.M.
      • Kwolek C.J.
      • Watkins M.T.
      • et al.
      Long-term outcomes after endovascular abdominal aortic aneurysm repair: the first decade.
      ,
      • De Bruin J.L.
      • Baas A.F.
      • Buth J.
      • Prinssen M.
      • Verhoeven E.L.
      • Cuypers P.W.
      • et al.
      Long-term outcome of open or endovascular repair of abdominal aortic aneurysm.
      Only the Endurant stent graft system (W.L. Gore, AZ, USA) was used in ENGAGE, whereas a multitude of stent grafts were used in the studies of this meta-analysis. Migration rates in patients treated with Cook Zenith grafts are similarly low (0.7%), suggesting that migration rates in newer generation stent grafts are inherently lower than earlier systems.
      • Mertens J.
      • Houthoofd S.
      • Daenens K.
      • Fourneau I.
      • Maleux G.
      • Lerut P.
      • et al.
      Long-term results after endovascular abdominal aortic aneurysm repair using the Cook Zenith endograft.
      Ultimately, there are currently insufficient data to determine whether endoanchors deployed during the primary procedure truly have an effect on graft migration, particularly when compared with results from the latest generation of stent graft systems.
      Sac growth is an important complication of proximal endoleak and migration as well as a major predictor for re-intervention and worse outcome. In this review, 55.3% of primary endoanchored EVAR patients had a decrease in sac diameter >5 mm at 12 month follow up. In a matched subgroup comparison from the ANCHOR registry, sac regression was significantly greater in patients treated with endoanchors than without (81.1 vs. 48.7%),
      • Muhs B.E.
      • Jordan W.
      • Ouriel K.
      • Rajaee S.
      • de Vries J.P.
      Matched cohort comparison of endovascular abdominal aortic aneurysm repair with and without EndoAnchors.
      suggesting that effective proximal neck sealing with endoanchors may contribute to sac regression.
      The use of endoanchors during secondary procedures, for treatment of TIaE and/or graft migration, is another important indication. Of the 74 secondary patients available at 10.7 month follow up, 22.6% had a post-operative TIaE. Of those treated exclusively for TIaE, 39.3% continued to have persistent endoleak despite endoanchors. Alternative strategies such as proximal endograft extension may have better outcomes for treating established TIaE.
      • Perini P.
      • Bianchini Massoni C.
      • Mariani E.
      • Ucci A.
      • Fanelli M.
      • Azzarone M.
      • et al.
      Systematic review and meta-analysis of the outcome of different treatments for type 1a endoleak after EVAR.
      On the other hand, endoanchors in this review prevented and treated all graft migrations in the secondary cohort. However, the small sample size and lack of long term follow up negates definitive conclusions for endoanchor treatment of established complications.
      There were a high number of aneurysm related re-interventions in the EVAR group. However, the majority occurred in a single study and were attributed to manufacturing discrepancies in the early design of the Aptus endograft (Aptus Endosystems, CA, USA).
      • Mehta M.
      • Henretta J.
      • Glickman M.
      • Deaton D.
      • Naslund T.C.
      • Gray B.
      • et al.
      Outcome of the pivotal study of the Aptus endovascular abdominal aortic aneurysms repair system.
      Endoanchor specific complications are sparse, with the most common being related to endoanchor fracture or maldeployment. Endoanchor limitations including poor penetration of mural calcification as well as the distance between the graft and the aortic wall can contribute to maldeployment. One TEVAR patient died from an irretrievable maldeployed endoanchor resulting in aortic dissection. Pre-procedural planning, meticulous device use, and increased operator experience should be able to identify landing zone areas unsuitable for endoanchor deployment or those patients in whom alternative strategies would be more favourable.
      There are sparse data for use of endoanchors in TEVAR and no meaningful conclusions can be drawn. The relatively high TEVAR mortality rate may be attributed to the poor pre-morbid state of patients and complexity of the endograft procedures. Further studies are required to assess endoanchors in TEVAR.
      There are several important limitations of this review; the most significant being the lack of case controlled and long term follow up data. Longer follow up data from the ANCHOR registry, out to 36 months, were presented at the 2018 VEITH symposium.
      • Jordan W.D.
      3-Year Results from the ANCHOR Registry: how EndoAnchors can improve EVAR results and salvage (some) failed EVARs.
      These data demonstrated that the rates of TIaE and graft migration were 1.7% and 0% in primary patients and 2.4% and 0% in secondary patients, respectively. However, the same limitations apply to these data as to the short term outcomes presented here. The small number of secondary EVAR patients as well as the high attrition rate at follow up were suboptimal. Furthermore, the use of proximal adjunctive procedures, such as aortic extension cuffs, could not be accounted for probably adding bias in favour of endoanchors. Weighted aortic neck characteristics were generally favourable, and specific conclusions cannot be drawn in treating patients with challenging anatomy. Furthermore, the current literature does not address the cost effectiveness of endoanchors, which can nearly double the cost of a standard EVAR procedure.
      • Chaudhuri A.
      Commentary: is an ounce of endoanchors worth more than many pounds for reintervention?.
      In conclusion, endoanchors appear to be a conceptually appealing addition to the growing EVAR armamentarium. Endoanchor fixation in EVAR is technically feasible and generally safe, with short term outcomes at least comparable to the latest generation of stent grafts. Endostapling in TEVAR is associated with lower technical success, higher peri-operative mortality, and potential serious adverse events. The current evidence is hindered by short term follow up and lack of case controlled trials, among other drawbacks, to recommend endoanchor use in routine clinical practice.

      Conflict of Interest

      None.

      Funding

      None.

      Appendix A. Supplementary data

      The following is the Supplementary data to this article:

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