Interventional procedure overview of endoanchoring systems in endovascular aortic aneurysm repair
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Summary of key evidence on endoanchoring systems in endovascular aortic aneurysm repair
Study 1 Qamhawi Z (2020)
Study type | Systematic review and meta-analysis |
|---|---|
Country | Not reported for individual studies |
Recruitment period | Search date: June 2019 |
Study population and number | n=628 (562 patients had EVAR and 66 had TEVAR) Patients who had EVAR or TEVAR with endoanchor fixation (prophylactic or therapeutic) |
Age and sex |
|
Patient selection criteria | Inclusion criteria for studies: original cohort studies of patients who had EVAR or TEVAR with endoanchor fixation and outcome measures included descriptive rates of type 1a endoleak, graft migration, and complications after endoanchor fixation. Data sources were PubMed/ MEDLINE, Embase, and the Cochrane Library. There were no language limitations. Multiple publications corresponding to a single cohort study were considered to be part of a single entity. Scientific abstract articles, studies of 5 or fewer patients, and pre-clinical studies were excluded. A study that used the Anson Refix Endostapler device (Lombard Medical Technologies, UK) was excluded from the review because the device was no longer commercially available. |
Technique | Endoanchoring system: Heli-FX EndoAnchor system. Various grafts were used, including Aptus, Gore Excluder, Endurant, Zenith, Incraft, Talent, AneuRx, Cook, Gore, Medtronic. Some patients had adjunctive proximal procedures alongside endoanchors. |
Follow up |
|
Conflict of interest/source of funding | None |
Analysis
Follow-up issues: The authors noted there was a high attrition rate at follow up.
Study design issues: The systematic review was conducted according to the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. Inclusion criteria were met by 14 single arm, open label studies. The median Newcastle-Ottawa score was 5 (range 5 to 6). There were no case controlled trials. Nine studies were included in the meta-analysis. The use of proximal adjunctive procedures, such as aortic extension cuffs, was not accounted for. For TEVAR, the meta-analysis was combined for primary and secondary procedures as outcomes were not consistently distinguished between the 2 subgroups.
Study population issues: Weighted aortic neck characteristics were generally favourable. In most patients, the endoanchoring system was used prophylactically during a primary EVAR (n=381).
Of the 9 studies included in the meta-analysis, 2 were also included in the systematic review by Karaolanis et al. (2020). Results from the ANCHOR registry were included in both systematic reviews, but from different publications.
Key efficacy findings
Number of patients analysed: 628 (562 EVAR, 66 TEVAR)
Indication for endoanchor | Number of patients, n (%) | Technical success %, weighted mean (95% CI) | Follow up period in months, weighted mean (95% CI) | Patients completed follow up, n (%) | Follow up type 1a endoleak %, weighted mean (95% CI) | Follow up graft migration %, weighted mean (95% CI) |
|---|---|---|---|---|---|---|
Primary fixation | 455 | 98.4 (95.7 to 99.8) | 15.4 (1.8 to 29.0) | 288 (63.3) | 3.5 (1.7 to 5.9) | 2.0 (0.12 to 6.0) |
Prophylaxis | 381 (83.7) | - | - | 233 (59.1) | 2.8 (1.1 to 5.3) | 2.2 (0.22 to 6.3) |
Intraoperative type 1a endoleak | 70 (15.4) | - | - | 51 (72.8) | 8.2 (1.9 to 18.2) | 0 |
Graft maldeployment | 4 (0.88) | - | - | 4 (100) | 0 | 0 |
Secondary fixation | 107 | 91.8 (86.1 to 96.2) | 10.7 (7.8 to 13.6) | 74 (69.2) | 22.6 (9.1 to 40.0) | 0 |
Type 1a endoleak alone | 60 (56.1) | - | - | 44 (73.3) | 39.3 (26.0 to 53.5) | 0 |
Graft migration | 12 (11.2) | - | - | 7 (58.3) | 0 | 0 |
Type 1 endoleak and/or graft migration | 35 (32.7) | - | - | 23 (65.7) | 6.6 (0.5 to 19.3) | 0 |
Aneurysm related reinterventions, n=136 (122 [89.7%] were in 74 patients in a single study)
Reinterventions for endoanchor failure, n=3
In a reported 196 primary EVAR patients, aneurysm sac diameter decreased by more than 5 mm in 55.3% (95% CI 41.3 to 69.0, I2=65.1%, p=0.057) of patients. There was no change in 43.5% (95% CI 29.5 to 58.9, I2=69.1%, p=0.040) of patients, while sac diameter increased by more than 5 mm in 1.4% (95% CI 0.25 to 3.5, I2=0%, p=0.70) of patients after endoanchor fixation.
EVAR with secondary fixation (n=107)
Aneurysm related reinterventions, n=13
Reinterventions for endoanchor failure, n=8
TEVAR (29 primary, 31 secondary, 6 indeterminate)
Technical success=90.3% (95% CI 72.1 to 99.4, I2=54.0%, p=0.11)
Overall rate of type 1a endoleak=8.7% (95% CI 1.0 to 18.9%, I2=64.4%, p=0.060) at follow up
There were no graft migrations.
Aneurysm related reinterventions, n=9
Reinterventions for endoanchor failure, n=1
Key safety findings
Adverse events in EVAR cohort
Endoanchor fracture, n=3
Dislocated endoanchor, n=3
Entrapped endoanchor needing snare retrieval, n=1
Common iliac artery dissection caused by wire manipulation needing a covered stent, n=1
All cause 30-day mortality=0.82% (95% CI 0.20 to 1.85, I2=0%, p=0.8)
Adverse events in TEVAR cohort
Maldeployed endoanchor, n=2; in 1 patient, the endoanchor was irretrievable resulting in a retrograde type A aortic dissection and death.
Weighted all cause 30-day mortality=11.9% (95% CI 5.4 to 20.6, I2=0%, p=0.59)
Deaths not directly attributed to endoanchor use, n=6 (2 respiratory failure, 1 ruptured thoracic aneurysm from undiagnosed endoleak, 1 intracranial haemorrhage, 1 ruptured iliac artery aneurysm, and 1 multiple visceral or cerebral infarctions).
Study 2 Karaolanis G (2020)
Study type | Systematic review and meta-analysis |
|---|---|
Country | Not reported for individual studies |
Recruitment period | Search date: July 2019 |
Study population and number | n=968 (8 articles) Patients who had endoanchors placed during an initial EVAR to prevent or repair intraoperative type 1a endoleak (prophylactic or therapeutic). |
Age and sex | Mean 73.4 years; 81.4% (627/770) male (not reported in 1 study of 198 patients) |
Patient selection criteria | English language studies reporting on primary use of endoanchors in patients having standard EVAR with or without unfavourable aortic neck were considered eligible. Primary use of endoanchors was defined as the placement of endoanchors during the initial EVAR to prevent or repair intraoperative type 1a endoleak. Only studies with 10 or more patients were included in the meta-analysis, while case reports, series with fewer than 10 patients and reviews of the literature were excluded from the analysis. Studies that referred to implantation of endoanchors but did not report outcome data were excluded. Duplicates were excluded, while in the case of metachronous publications from the same surgical group, only the latest article or the article with the largest number of patients was included. |
Technique | Endoanchor device: Aptus Heli-FX EndoAnchor System (Medtronic Vascular, US) Endoanchors were used for prophylaxis in 742 (77%) patients and to treat an intraoperative type 1a endoleak in 127 (13%) patients. The mean number of endoanchors deployed per patient was 4 in 2 studies and 5 in 5 studies, only 1 study used 6 endoanchors. |
Follow up | Mean 10 months (mean imaging follow up was 6 months) |
Conflict of interest/source of funding | None for the systematic review. |
Analysis
Follow-up issues: The authors noted that the limited follow-up period of the eligible studies precluded a long-term assessment of the utility of the endoanchors as a definite prophylactic adjunct.
Study design issues: There were no randomised controlled trials. Of the 8 included studies, 4 were prospective and 4 were retrospective. The meta-analysis was done according to The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The Newcastle–Ottawa tool was used to evaluate the methodologic quality of the studies. The maximum possible score for a study is 9, based on 3 broad perspectives: (1) selection of the study groups, (2) comparability of the groups and (3) ascertainment of outcome of interest. The median score of the 8 included articles was 6 (range 5 to 6). The main early outcome was the technical success and late outcomes included the incidence of type 1a endoleak, migration and the number of patients who had regression or expansion of the aneurysm sac throughout the follow-up period. Secondary outcome endpoints were the freedom of aneurysm-related reintervention, the rate of aneurysm rupture and the overall survival rate. There were differences in definitions and follow-up imaging between the studies, which contributed to heterogeneity. There was a lack of information about the co-existence of type 2 endoleaks, which may have led to persistence of low flow type 1a endoleaks.
Study population issues: Anatomical neck characteristics of hostile neck were reported only in 2 studies, including 116 patients.
Of the 8 studies, 2 were also included in the systematic review by Qamhawi et al. (2020). Results from the ANCHOR registry were included in both systematic reviews, but from different publications.
Key efficacy findings
Number of patients analysed: 968
Technical success (defined as successful implantation of endoanchors with adequate penetration of the aortic wall and absence of a type 1a endoleak at completion angiography = 97.1% (95% CI 93.0 to 99.7; 6 studies; I2=66.9%, p=0.01)
Incidence of type 1a endoleak after primary use of endoanchors = 6.2% (95% CI 0.8 to 15.3; 5 studies; I2=90.3%, p=0.00) These endoleaks were detected on CT angiography during a mean follow-up period of 6 months (range 17 ± 12.14 months).
Migration of main graft (needing an additional proximal aortic cuff because of persistent type 1a endoleak = 0.3% (95% CI 0.0 to 1.5; 5 studies; I2=0.0%)
Regression of the aneurysmal sac = 68.8% (95% CI 51.0 to 84.2; 6 studies; I2=95.3%, p=0.00)
Expansion of the aneurysmal sac = 1.9% (95% CI 0.9 to 3.2; 6 studies; I2=0.0%)
Freedom of aneurysm-related reintervention (mean follow-up 10 months) = 97.7% (95% CI 95.2 to 99.4; 4 studies)
Overall survival (mean follow-up 10 months) = 93.4% (95% CI 90.0 to 96.3; 4 studies)
Results in patients with 'hostile neck' characteristics (n=116, 2 studies)
Crude rate of type 1a endoleak after primary use of endoanchors = 19.6% (18/92)
Crude rate of type 2 endoleak during follow up = 18.1% (21/116)
Proportion of patients needing additional proximal aortic cuff because of graft migration = 0.9% (1/116)
Reintervention rate = 6.9% (8/116)
Key safety findings
Misdeployment of the endoanchors at the end of the procedure was observed in a 'few cases' because of a heavily calcified aorta. This was resolved using additional staples for better fixation of the endograft. In the short-term follow-up period, no other additional complication related to endoanchors was reported.
No aneurysm rupture was recorded during follow up (4 studies).
In the 116 patients with hostile neck characteristics, there was no aneurysm-related mortality and mortality not related to the procedure was 5.2% (6/116).
Study 3 Muhs B (2018)
Study type | Non-randomised comparative study (using data from ANCHOR registry) |
|---|---|
Country | US and The Netherlands |
Recruitment period | 2009 to 2014 |
Study population and number | n=198 (99 EVAR with prophylactic endoanchoring system, 99 EVAR alone) Patients who had EVAR of abdominal aortic aneurysm |
Age and sex | Not reported |
Patient selection criteria | Patients with asymptomatic, symptomatic, or ruptured abdominal aortic aneurysms were eligible for study inclusion. Patients who had prophylactic endoanchor treatment were assessed by investigators to be at high risk for later complications, with most meeting at least 1 hostile neck criterion (aortic diameter at the renals >28 mm, proximal neck length <10 mm, infrarenal angulation to bifurcation >60 degrees, neck thrombus thickness ≥2 mm, neck thrombus circumference >180 degrees, neck calcium thickness ≥2 mm, and neck calcium circumference >180 degrees). |
Technique | Endoanchoring device: Aptus Heli-FX EndoAnchor System (Medtronic, US) In the endoanchor group, endoanchors were used at the time of the primary EVAR procedure, either to treat perioperative type 1a endoleak or for prophylaxis of neck-related complications. Control group: patients had conventional EVAR without adjunctive use of endoanchors. In both groups, the Medtronic Endurant endograft was the most commonly used device for EVAR. Other devices included Medtronic Talent, Gore Excluder, Cook Zenith, Lombard Aorfix, Endologix AFX or Powerlink and TriVascular Ovation. |
Follow up | 2 years |
Conflict of interest/source of funding | Medtronic sponsored the ANCHOR arm of the study. 1 author disclosed clinical research grants and consulting fees from Medtronic, Gore, Cook, and Endologix. 1 author disclosed consulting fees from Medtronic, Cook, and Endologix and also that he was the former CEO of Aptus. 1 author disclosed that he was employed by and held equity in Syntactx, a company that received research funding from Medtronic (the sponsor of the work). 1 author disclosed clinical research grants from Endologix and consulting fees from Medtronic and Endologix. |
Analysis
Study design issues: Retrospective comparison of propensity-matched cohorts, matched on the basis of anatomic criteria. Consent was limited to baseline and follow up imaging for the control cohort, so there was a lack of clinical outcome data. Standardised differences between baseline anatomical characteristics were calculated using Cohen's effect size classifications for small, medium, large, and very large effect sizes (0.2, 0.5, 0.8, and 1.3, respectively). A standardised difference less than 0.2 was determined to indicate a minimal imbalance between the cohorts.
Study population issues: There was a lack of baseline demographic data and procedural data for control patients, so matching was done on anatomic criteria alone.75% of patients in the endoanchor group and 56% of patients in the control group met at least 1 criterion for hostile neck. The most common hostile neck characteristic observed in each cohort was severe aortic neck calcification, seen in 33% of patients in the endoanchor group and 27% of patients in the control group. There were large differences between the cohorts with regard to proximal and visual neck length (control patients had longer proximal and visual necks, on average). A very large difference was calculated for thrombus circumference (mean 37.2° for the endoanchor group compared with 22.9° in the control group). The standardised difference between the overall anatomic profile of the 2 cohorts was calculated as -0.2, the threshold determining a small difference. Cox regression analyses were done to assess whether any variables were predictive for later aneurysm sac regression.
Other issues: patients from the ANCHOR registry have been included in several other publications, including the systematic review by Qamhawi et al., 2020.
Key efficacy findings
Number of patients analysed: 198 (99 endoanchor, 99 control)
Endoleaks and migration
At 1 year, 2 patients in the endoanchor group and 4 patients in the control group had a type 1a endoleak. There were no further type 1a endoleaks reported through 2-year follow-up.
Freedom from type 1a endoleak at 1 and 2 years (Kaplan-Meier analysis):
Endoanchor group=97% ± 2.1%
Control group=94.1% ± 2.5%, p=0.34
At 1 year, 15 patients in the endoanchor group and 17 patients in the control group had a type 2 endoleak. One additional patient in the control group had a type 2 endoleak at 2-year follow-up.
At 1 year, 4 patients in the endoanchor group and 1 patient in the control group had a type 3 endoleak.
There was no migration more than 10 mm in either group within 2 years.
Neck dilation and aneurysm enlargement
Neck dilation 4 mm or more was reported in 3 patients in the endoanchor group and 8 in the control group within 2 years.
Freedom from neck dilation at 1 year (Kaplan-Meier analysis):
Endoanchor group=98.4% ± 1.6%
Control group=94.9% ± 2.5%, p=0.27
Freedom from neck dilation at 2 years (Kaplan-Meier analysis):
Endoanchor group=90.4% ± 5.6%
Control group=87.3% ± 4.3%, p=0.46
Aneurysm enlargement more than 5 mm at 2 years was reported in 2 patients in the endoanchor group and 4 in the control group.
Freedom from aneurysm enlargement at 1 year (Kaplan-Meier analysis):
Endoanchor group=97.0% ± 2.1%
Control group=96.0% ± 2.3%, p=0.89
Freedom from aneurysm enlargement at 2 years (Kaplan-Meier analysis):
Endoanchor group=97.0% ± 2.1%
Control group=94.0% ± 3.0%, p=0.67
Aneurysm sac regression
At 1 year, 29 patients in the endoanchor group and 25 in the control group had aneurysm sac regression. At 2 years, an additional 6 patients in the endoanchor group and 11 in the control group had sac regression.
Cox regression analysis found an inverse correlation between number of hostile neck criteria met and later sac regression (p=0.05). With each increase in number of hostile criteria met, patients were 23% less likely to experience later sac regression (p=0.046). No other baseline or procedural variables were found to be statistically significantly associated with later sac regression, apart from treatment received (EVAR with or without endoanchors), which was found to be predictive in all multivariate analyses.
Cumulative incidence of aneurysm sac regression at 1 year (Kaplan-Meier analysis):
Endoanchor group=53.5% ± 7.0%
Control group=32.3% ± 5.3%, p=0.03
Cumulative incidence of aneurysm sac regression at 2 years (Kaplan-Meier analysis):
Endoanchor group=81.1% ± 9.5%
Control group=48.7% ± 5.9%, p=0.01
Predictive variable | Endoanchor group – regression, n=64 | Endoanchor group – no regression, n=35 | p | Control group – regression, n=63 | Control group – no regression, n=36 | p |
|---|---|---|---|---|---|---|
Neck thrombus circumference, degrees | 38 (76); 0 to 320 | 35 (60); 0 to 175 | 0.85 | 35 (66); 0 to 300 | 2 (9); 0 to 54 | 0.003 |
Infrarenal neck diameter, mm | 25 (4); 17 to 37 | 25 (4); 20 to 34 | 0.89 | 26 (4); 18 to 35 | 24 (3); 17 to 29 | 0.004 |
Outcome | Endoanchor group – with thrombus, n=30 | Endoanchor group – no thrombus, n=69 | p | Control group – with thrombus, n=18 | Control group – no thrombus, n=81 | p |
|---|---|---|---|---|---|---|
Sac regression | 10 (33) | 25 (36) | 0.82 | 1 (6) | 35 (43) | 0.001 |
No sac regression | 20 (67) | 44 (64) | 17 (94) | 46 (57) |
Outcome | Endoanchor group – infrarenal diameter >28 mm, n=18 | Endoanchor group – infrarenal diameter <28 mm, n=81 | p | Control group – infrarenal diameter >28 mm, n=21 | Control group – infrarenal diameter <28 mm, n=78 | p |
|---|---|---|---|---|---|---|
Sac regression | 8 (44) | 27 (33) | 0.50 | 2 (10) | 34 (44) | 0.004 |
No sac regression | 10 (56) | 54 (67) | 19 (90) | 44 (56) |
Key safety findings
No safety data were reported.
Study 4 Jordan W (2014)
Study type | Cohort study (ANCHOR registry, NCT01534819) |
|---|---|
Country | US, The Netherlands, Germany, Italy, UK (43 sites) |
Recruitment period | 2012 to 2013 |
Study population and number | n=319 (242 primary, 77 revision) Patients who had prophylactic or therapeutic endoanchor implantation with EVAR |
Age and sex | Mean 74.1 years; 74.6% (238/319) male |
Patient selection criteria | Eligible patients included those with asymptomatic, symptomatic, or ruptured abdominal aortic aneurysm, adequate iliofemoral access, life expectancy of 1 year or more and no history of allergy to the metallic components of the device. Exclusion criteria included prior endoanchor implantation, known bleeding diathesis, infection, and significant proximal aortic neck thrombus or calcium that would preclude adequate endoanchor penetration into the aortic wall. |
Technique | Device: Heli-FX EndoAnchor System (Aptus Endosystems, US) The primary arm comprised those patients with endoanchor implantation at the same procedure as the initial EVAR procedure. Patients in the primary arm were treated for prophylaxis of endoleak or migration when, in the opinion of the investigator, the anatomy put the patient at risk for future proximal aortic neck complications. Patients were also included in the primary arm when endoanchors were used to treat a type 1a endoleak evident at the time of an initial EVAR procedure. The revision arm included patients who had prior EVAR and presented with type 1a endoleak or endograft migration. Aortic extender cuffs were usually used in this group when the original endograft was not adequately juxtaposed to the lowest renal artery, from either migration or misdeployment. Suitable endografts included the Zenith (Cook, US), the Excluder (WL Gore, US) and the AneuRx, Talent, or Endurant devices (Medtronic Vascular, US). The median number of endoanchors deployed was 5 in the primary arm and 7 in the revision group. Most procedures (89%) were done under general anaesthesia. |
Follow up | Mean 9.3 months |
Conflict of interest/source of funding | 7 authors have received research grants or fees from companies including WL Gore & Associates, Medtronic Inc, Aptus Endosystems Inc, Endologix, Lombard Medical Technologies, Trivascular Inc, Cordis Corporation, Bolton Medical Inc, Abbott Vascular Inc, Terumo Cardiovascular Systems Corp, Cook Medical, MEDRAD Inc, Silroad Medical. 1 author has equity ownership in and is employed by Syntactx, a company that receives fees for contract research activities from Aptus Endosystems Inc. |
Analysis
Follow-up issues: Follow-up was done according to each investigator's standard of care.
Study design issues: Single-arm, prospective, multicentre, multinational registry. Consent could be obtained before endoanchor implantation or within 30 days after endoanchor implantation to include those patients with unplanned use of the device. To exclude selection bias, investigators were asked to enrol patients before the first postoperative imaging study. The primary efficacy end point was successful implantation of the minimum number of endoanchors as defined in the Instructions for Use with respect to the diameter of the aortic neck and freedom from endograft migration or type 1a endoleak at 12 months. The primary safety end point was a composite defined as freedom from serious adverse device-related events or procedure-related adverse events during 12 months, excluding those events solely attributable to the endograft or the endograft implantation procedure but including aneurysm-related mortality. Technical success was defined as deployment of the desired number of endoanchors with adequate penetration of the vessel wall and without endoanchor fracture and with uneventful removal of the Heli-FX Guide. Procedural success was defined as technical success without a type 1a endoleak at completion angiography.
Study population issues: Aneurysms were asymptomatic in 87.8% of patients and symptomatic in 12.2%. Ruptured aneurysms were reported in 1.0% of patients. The American Society of Anesthesiologists physical status was 1 in 3 patients (0.9%), 2 in 29 patients (8.9%), 3 in 228 patients (71.5%), and 4 in 59 patients (18.5%). The mean aneurysm diameter at the time of the procedure was 58 mm. The mean proximal aortic neck was 16 mm in length (42.7% were less than 10 mm and 42.7% were conical) and 27 mm in diameter; infrarenal neck angulation was 24 degrees.
Key efficacy findings
Number of patients analysed: 319 (242 primary, 77 revision)
Technical success
All patients=95.0%
Primary group=96.3%
Revision group=90.9%
Procedural success
All patients=87.5%
Primary group=89.7%
Revision group=80.5%
Freedom from type 1a endoleak at completion angiography
All patients=90.9%
Primary group=92.1%
Revision group=87.0%
Secondary intervention | Primary group, n=242 | Revision group, n=77 | All, n=319 |
|---|---|---|---|
Open surgical conversion | 0 | 0 | 0 |
Repair of type 1a endoleak | 1 (0.4) | 7 (9.1) | 8 (2.5) |
Treatment of type 2 endoleak | 1 (0.4) | 4 (5.2) | 5 (1.6) |
Treatment of migration | 0 | 0 | 0 |
Treatment of graft limb kinking | 1 (0.4) | 1 (1.3) | 2 (0.6) |
Treatment of graft limb occlusion | 2 (0.8) | 1 (1.3) | 3 (0.9) |
Treatment of access vessel injury | 1 (0.4) | 0 | 1 (0.3) |
Lower extremity revascularisation | 2 (0.8) | 1 (1.3) | 3 (0.9) |
Total secondary procedures | 7 (2.9) | 11 (14.3) | 18 (5.6) |
Total patients with secondary procedures | 7 (2.9) | 7 (9.1) | 14 (4.4) |
Note: some procedures addressed more than 1 indication
Of the 18 secondary procedures, 8 (44.4%) were within 30 days of the index procedure, 5 (29.4%) were between 31 and 90 days, and 5 (29.4%) were more than 180 days after the index procedure.
Key safety findings
Primary safety endpoint
All patients=92.2% (294/319)
Primary group=93.4% (226/242)
Revision group=88.3% (68/77)
'No patient experienced an unanticipated adverse device effect.'
Mortality
There were 9 deaths during follow-up (2.8%), none of which was aneurysm related or device related.
Study 5 Valdivia A (2021)
Study type | Cohort study (PERU registry, NCT04100499) |
|---|---|
Country | Greece, Italy, The Netherlands, Spain, UK, US (7 centres) |
Recruitment period | 2010 to 2019 |
Study population and number | n=221 (175 primary, 46 revision) Patients who had endoanchoring systems used to prevent or repair failure during infrarenal endovascular aneurysm repair |
Age and sex | Mean 75.6 years; 83% (184/221) male |
Patient selection criteria | The decision to use endoanchors was made by the treating surgeon or multidisciplinary aortic committee according to each centre's practice. All on-label cases were included. Hostile neck conditions, including severely angulated necks were not considered a reason for exclusion. "Hostile neck" was defined as neck length <10 mm and 1 or more of the following criteria: infrarenal angle >60°, thrombus with >2 mm thickness in >50% circumference or circumferential calcification >50%, conical neck (gradual neck dilation >2 mm) along the 10 or 15 mm infrarenal neck length, and diameter >28 mm or asymmetric neck bulge(s). Patients included in the ANCHOR registry were excluded from this analysis. |
Technique | Endoanchoring device: Heli-FX EndoAnchor System (Medtronic Vascular, US) The primary group (79.2%) included all patients who had endoanchors as a preventive measure or for an intraoperative type 1a endoleak and the revision group (20.8%) included those patients where endoanchors were used (either alone or with adjunctive endografts) to treat a post-EVAR failure (migration alone, type 1a endoleak, or both). Of the 221 patients, 193 (87.3%) had suprarenal fixation endografts, with the Endurant endograft (Medtronic, US) being the most common (n=112; 50.7%). Other endografts included Incraft (Cordis Corporation, US) and E-Tegra (JOTEC GmbH, Germany). The median number of endoanchors deployed per patient was 6. Adjunctive procedures were used in 10.9% (24/221) of patients. |
Follow up | Median 27 months (interquartile range 12 to 48) |
Conflict of interest/source of funding | The authors received no financial support for the research, authorship, and publication of this article. Of the 14 authors, 7 are consultants for Medtronic. |
Analysis
Follow-up issues: Follow-up imaging was scheduled according to each centre's protocol and included either abdominal ultrasound or radiography or CT scan imaging.
Study design issues: Observational retrospective study of prospectively collected data from 7 vascular surgery departments. The main outcomes were technical success, freedom from type 1a endoleak and sac diameter evolution. Technical success was defined as freedom from type 1 endoleak at the end of the primary procedure, where endoanchors were deployed, at 30 days follow-up, and during any period of continued follow-up. Aneurysm-related mortality was defined as any death because of rupture or death within 30 days of the procedure.
Study population issues: Of the 221 patients, 199 (90%) were considered high-risk by the American Society of Anesthesiology classification (score 3 to 4). Conical shape was the most frequent hostile neck condition, noted in 82 (38%) patients.
Key efficacy findings
Number of patients analysed: 221
Technical success
Initial technical success=89.1% (197/221); 23 patients had type 1a endoleak after the procedure, all of which were managed conservatively. One of these patients died immediately after the operation because of multi-organ failure.
30-day technical success=95.5% (211/221); 4 patients had persistent type 1a endoleak and 2 had new type 1a endoleaks that had not been identified at the end of the index procedure. Of these 6 patients, 2 had aortic banding by open surgery, 3 had endovascular treatment with a large balloon-expanding stent and 1 had conservative management.
Follow-up technical success=95.5% (211/221); 5 patients had new type 1a endoleaks, 1 had reappearance of a spontaneously sealed type 1a endoleak and 4 patients had new type 1b endoleaks. Of these 10 patients, 6 had endovascular treatment, 1 had open surgery and 3 had conservative management.
Freedom from type 1a endoleak at 24 months
All patients=94%
Primary group=96%
Revision group=86%, p=0.036
Reintervention at 24 months
Freedom from neck related reinterventions=98%
Freedom from any reintervention=87%
Survival at 2 years
Freedom from all-cause mortality=89%
Freedom from aneurysm-related mortality=98%
Aneurysm sac evolution
Sac size before procedure=66.3mm ± 15.1
Sac size after procedure= 61.7mm ± 17.5, p<0.001
In the 180 patients with at least 6 months of imaging follow-up, 41.1% showed sac regression, 51.1% remained stable and sac growth was reported in 7.8% of patients.
Key safety findings
Endoanchor deployment issues
Fractures, n=4 (no treatment)
Losses, n=4 (2 were snared, 1 was caged and 1 was left in main endograft body)
Twisted device, n=2 (catheter was changed)
None of these caused any type of intraoperative or follow-up complication or failure.
Mortality
Aneurysm-related deaths, n=4 (within 30 days)
Multiorgan failure, n=1
Sepsis, pneumonia, n=2
Endograft infection, n=1
Non-aneurysm-related deaths, n=21
Neoplasm, n=8 (at 10, 11, 14, 14, 15, 42, 43 and 44 months)
Cardiac, n=4 (at 5, 11, 23 and 49 months)
Sepsis, n=2 (at 2 and 9 months)
Respiratory, n=1 (at 12 months)
Unknown cause, n=6 (at 3, 16, 20, 31, 34 and 38 months)
Study 6 Mehta M (2014)
Study type | Single-arm study |
|---|---|
Country | US (25 sites) |
Recruitment period | 2007 to 2009 |
Study population and number | n=155 Patients who had EVAR with endoanchors for abdominal aortic aneurysm |
Age and sex | Mean 73 years; 93.5% male |
Patient selection criteria | Inclusion criteria included: age 21 years or above; male or nonpregnant female; infrarenal abdominal aortic aneurysm with a maximum diameter 4.5 cm or more, at least 12 mm length of nonaneurysmal proximal neck, a proximal neck internal diameter between 19 and 29 mm, an internal diameter at the aortic bifurcation 18 mm or more, an angle of 60 degrees or less relative to the long axis of the aorta; bilateral iliac artery distal fixation sites 10 mm or more in length; the resultant repair should preserve patency in at least 1 hypogastric artery; bilateral iliac arteries with an internal diameter between 9 and 20 mm; bilateral femoral/iliac arteries with morphology (minimal thrombus, calcium, or tortuosity) compatible with standard vascular access techniques, and vessel size must accommodate a 16F (5.3 mm) or 18F (6.0 mm) delivery system; candidate for elective surgical repair; life expectancy more than 2 years. Exclusion criteria included: myocardial infarction within past 10 weeks; active systemic infection; ruptured or leaking, mycotic or inflammatory abdominal aortic aneurysm; connective tissue disorders; concomitant thoracic or thoracoabdominal aortic aneurysms; previous abdominal aortic aneurysm repair; patients with a body habitus that would prevent imaging required by the study; significant comorbid conditions that, in the opinion of the investigator, pose undue risk of general anaesthesia or endovascular surgery; patient requires additional planned major procedure at the time or within 30 days; dialysis dependent renal failure or creatinine concentration >2.5 mg/dL; allergy to or intolerance of radiopaque contrast agents that cannot be adequately pretreated or would prevent imaging required by the study; known sensitivity or allergy to polyester, nickel, titanium, tantalum, chromium, molybdenum, or cobalt; patients who cannot discontinue oral anticoagulation or antiplatelet therapy at the time of the study procedure; history of bleeding diathesis or hypercoagulable condition; thrombus, calcification, or plaque 2 mm or more in thickness or 50% or more (180-degree) continuous coverage of the vessel circumference in the intended seal zone; irregularly shaped calcification or plaque that may compromise the fixation and sealing at the proximal or distal implantation sites. |
Technique | Device: Aptus endograft and EndoAnchors (Aptus Endosystems, US) The median number of endoanchors was 5 per patient (range 0 to 14) |
Follow up | Median 3.4 years (IQR 3.1 to 3.8 years) |
Conflict of interest/source of funding | 1 author is a consultant for Aptus,1 is an adviser to Abbot, Gore, and Trivascular, 1 receives research funding for clinical trials participation from Medtronic, Gore, Cook, Endologix, Trivascular, Cordis, and Aptus and is a consultant for Medtronic, Gore, Endologix, and Aptus, 1 receives an honorarium from and is a speaker for Gore, Trivascular, Aptus, Endologix, and IDEV and receives research funding for clinical trial participation from Gore, Medtronic, Aptus, Lombard, Bolton, Abbott, Cordis, Terumo, ev3, Trivascular, Maquet, and Harvest, 1 is a speaker for Medtronic and Gore and participates in clinical trials for Gore, Medtronic, and Aptus, and 1 is a consultant for Gore. |
Analysis
Follow-up issues: Patients had CT scans at 1, 6, and 12 months and then yearly thereafter through 60 months after implantation.
Study design issues: Prospective, multicentre, single-arm investigational device exemption trial. The primary safety end point of the study was the percentage of patients experiencing 1 or more major adverse events within 30 days of the index procedure (including death, myocardial infarction, stroke, renal failure, respiratory failure, or paralysis). The primary effectiveness end point of the study was the composite of delivery success and absence of type 1 or type 3 endoleaks needing intervention after the index procedure, migration, open surgical conversion, or aneurysm rupture within 1 year of the index procedure. Delivery success was defined as successful implantation of the endograft with a main body and 2 iliac limbs and delivery of at least 2 endoanchors at an appropriate treatment site within the proximal aortic neck. For the sample size calculation, the estimated major adverse events rate at 30 days was 4.6% for the primary safety end point, and the estimated treatment success for the effectiveness end point was 90.3%.
Study population issues: Aneurysms ranged in size from 4.2 to 9.4 cm, with a mean of 5.4 cm. The mean proximal aortic neck length was 22.1 mm (range 2 to 50 mm). The proximal neck length was less than 12 mm and less than 10 mm in 17% and 12% of patients, respectively. The mean infrarenal neck angulation was 32.1 degrees (range 3.1 to 71.7 degrees).
This study is also included in the systematic reviews by Qamhawi (2020) and Karaolanis (2020).
Key efficacy findings
Number of patients analysed: 155
Technical success
Successful device delivery=98.7% (153/155); 1 patient had conversion to open surgical repair before the placement of endoanchors after unsuccessful cannulation of the contralateral gate. The second patient had a different endovascular device after misdeployment of the main body of the endograft.
Treatment success
Primary effectiveness endpoint at 1 year=97.4% (151/155)
Type 1 and type 3 endoleaks were each reported in 1 patient within the first year of follow-up.
Type 2 leaks at 30 days=32.9% (49/149)
Type 2 leaks at 1 year=17.6% (23/131)
Endograft migration more than 1 cm=3.2% (5/155)
Overall survival
1 year=96.8%
2 years=96.1%
3 years=91.6%
Freedom from aneurysm related mortality at 1 year=99.4%
Diameter change | 6 months, n=140 | 1 year, n=131 | 2 years, n=107 | 3 years, n=82 |
|---|---|---|---|---|
decrease by more than 5 cm | 62 (44.3) | 79 (60.3) | 78 (72.9) | 67 (81.7) |
5 cm or less ('no change') | 77 (55.0) | 50 (38.2) | 26 (24.3) | 12 (14.6) |
increase by more than 5 cm | 1 (0.7) | 2 (1.5) | 3 (2.8) | 3 (3.7) |
Reinterventions
74 (47.7%) patients had a total of 122 secondary interventions, 92 of which were in patients with thrombus-related events.
Key safety findings
Mortality
30-day mortality=0.6% (1/155); cardiac death 18 days after an index procedure complicated by rupture of an iliac artery during balloon angioplasty of a graft limb.
There was 1 additional aneurysm-related death beyond 3 years caused by haemorrhagic stroke, adjudicated to be related to warfarin prescribed to treat a pulmonary embolism after an abdominal aortic aneurysm-related reintervention.
Event | 30 days | 1 year | 3 years |
|---|---|---|---|
Death | 1 (0.6) | 5 (3.2) | 15 (9.7) |
Myocardial infarction | 2 (1.3) | 7 (4.5) | 10 (6.5) |
Stroke | 0 (0) | 3 (1.9) | 7 (4.5) |
Renal failure | 0 (0) | 2 (1.3) | 6 (3.9) |
Respiratory failure | 0 (0) | 1 (0.6) | 3 (1.9) |
Paralysis | 0 (0) | 0 (0) | 0 (0) |
Any major adverse event | 3 (1.9) | 14 (9.0) | 30 (19.4) |
Thrombus-related events
62 (40.0%) patients had a total of 114 adverse events; in 98.4% (61/62) of these patients, the event was thrombus related.
32 (20.6%) patients had a total of 49 device-related thrombotic events within 1 year of implantation and 56 patients (36.1%) had 104 device-related thrombotic events within 3 years. Median time from implantation to first event in affected patients was 355 days (IQR 176 to 691 days; range 17 to 1477 days).
Limb occlusion=4.5% (7/155) at 1 year and 7.7% (12/155) at 3 years.
Distal embolic events linked to the endograft=9.7% (15/155) at 1 year and 14.8% (23/155) at 3 years.
Nonocclusive thrombus identified by imaging=9.7% (15/155) at 1 year and 21.3% (33/155) at 3 years.
A root cause analysis of thrombus-related events identified small, out-of-specification docking limbs with graft infolding and high local shear, resulting in thrombus formation within the endograft with subsequent distal embolisation in some patients.
The authors noted that the device was subsequently modified to reduce the rate of thrombus-related events.
Study 7 Masoomi R (2019)
Study type | Case series (MAUDE database) |
|---|---|
Country | US |
Recruitment period | 2011 to 2017 |
Study population and number | n=229 separate reports describing possible adverse events Device-related adverse events associated with the use of endoanchors in endovascular aneurysm repair |
Age and sex | Not reported |
Patient selection criteria | All events involving the name "Aptus Heli-FX EndoAnchor system" were identified on the MAUDE database. Four reports involving thoracic aortic aneurysm repair were excluded. |
Technique | Endoanchoring device: Aptus Heli-FX EndoAnchor system (Medtronic Vascular, US). |
Follow up | Not reported |
Conflict of interest/source of funding | None |
Analysis
Study design issues: The main aim of the study was to assess the safety of EndoAnchor use in routine clinical practice by extracting data from the publicly available MAUDE database. Information submitted to the MAUDE database has several limitations, including the possibility of inaccurate or incomplete data, and underreporting. There is a time delay between the event date and report date, which can lead to underestimation of overall incidence of adverse events. For these reasons, the MAUDE database cannot be used to accurately determine the true incidence of adverse events. Two members of the team reviewed all reports independently and reports were categorised as residual endoleak, dislodgement or fracture of the EndoAnchors, air embolism, guide or applier malfunction, and other adverse events. Duplicate reports and those deemed unrelated to the device were not included.
An estimate of the number of device systems used during the study period was obtained through direct correspondence with the manufacturer. This figure was quoted as around 7,000 systems used.
Study population issues: There was no information on aortic neck anatomy or patients' characteristics.
Other issues: the paper states that there were 229 separate reports, but the reported percentages appear to have used 213 as the denominator.
Key safety findings
Number of separate reports on MAUDE database=229, estimated total device systems used=7,000
Reported events by type
Failure to resolve or recurrence of a type 1A endoleak, n=123 (58% of reports; 1.7% of estimated total device systems used)
Device dislodgement or fracture, n=65 (31% of reports; 0.9% of estimated total device systems used). The fractured device embolised to the renal artery in 2 cases, hypogastric artery in 1 case, and the flow divider of the endograft in 1 case.
Air embolism, n=5 (0.07% of estimated total device systems used)
Guide or applier malfunction, n=20 (0.3% of estimated total device systems used)
There were 27 deaths reported during index hospitalisation or during follow up. Of those, 15 were of unknown aetiology or considered to be unrelated to the index procedure, and 12 reports were thought to be related to the index EVAR procedure rather than EndoAnchor use. There was 1 report where multiple tiny
holes were seen at the site of EndoAnchor insertion in fabric at the time of explant (and these were thought
by the reporting physician to have contributed to worsening endoleak).
No long-term clinical consequences were reported from the air embolisms or guide malfunctions.
The authors noted that most adverse events occurred in non-elective cases.
Study 8 Goudeketting S (2019)
Study type | Case series (subset of ANCHOR registry data) |
|---|---|
Country | US and the Netherlands |
Recruitment period | Not reported |
Study population and number | n=86 (61 primary and 25 revision) Patients who had therapeutic use of endoanchors |
Age and sex | 81% male |
Patient selection criteria | Patients from the ANCHOR registry were included in this study only if the indication for endoanchor use was to treat a type 1a endoleak and the first postprocedural CT angiography scan was of sufficient quality. Patients were excluded when aortic extension cuffs were implanted at the time of endoanchor implantation. The primary arm consisted of patients treated for an intraoperative type 1a endoleak; the revision arm comprised those with endoanchor implant use as a secondary intervention for type 1a endoleak or endograft migration after EVAR. |
Technique | Device: Heli-FX EndoAnchor System (Medtronic Vascular, US) 580 endoanchor implants were used. |
Follow up | 1 month |
Conflict of interest/source of funding | This research received a restricted grant from Medtronic, Inc. Three authors are consultants and on the Scientific Advisory Board for Medtronic, Inc. |
Analysis
Study design issues: The study used a subset of patients from the ANCHOR global registry. The aim was to analyse the relationship between endoanchor deployment and successful resolution of type 1a endoleaks, including their distribution along the circumference of the neck, penetration depth into the aortic wall, and angle of penetration. The study population was divided into a nonsuccessful and successful cohort on the basis of persistence of type 1a endoleak after treatment with endoanchor implants at 1-month follow up. Maldeployment was investigated for each endoanchor implant and defined as implants deployed above the fabric or in a gap more than 2 mm between the endograft and aortic wall (endograft malapposition) because of thrombus more than 2 mm in the infrarenal neck or positioning of the endoanchor implant below the aortic neck.
Study population issues: Median preoperative neck diameter was 26.5 mm (IQR, 24.2 to 28.8 mm).
Key efficacy findings
Number of patients analysed: 86
62% (53/86) of endoleaks had resolved at the 1-month CT angiography study.
17 (27.9%) patients in the primary arm and 16 (64.0%) in the revision arm had a persistent type 1a endoleak.
332 and 248 endoanchor implants were deployed in the cohorts with and without procedural success, respectively.
The median number of implants was 6 (IQR, 4 to 8) per patient in the 53 patients with successful resolution of the type 1a endoleak and 8 (IQR, 4 to 10) in the 33 patients with a persistent endoleak (p=0.06).
After exclusion of the maldeployed implants, 87.4% of the implants in the successful group had a good penetration compared with 68.8% in the cohort without procedural success.
Key safety findings
Maldeployment=29% (170/580) of endoanchor implants
In 33 patients of the successful group, a median of 1 [IQR, 1 to 3] implant was maldeployed. In the 21 patients with a persistent type 1a endoleak, a median of 4 [IQR, 3 to 6] implants were maldeployed.
7 (1%) implants were deployed above the fabric and 163 (28%) implants were deployed in a ≥2-mm gap between the endograft and aortic wall.
The amount of implants with good, borderline, and no penetration was still statistically significantly different between the procedural success and failure groups after exclusion of implants with maldeployment (success: 235 [87.4%], 14 [5.2%], and 20 [7.4%]; type 1a endoleak: 97 [68.8 %], 18 [12.8%] and 26
[18.4%]; p<0.001).
The authors noted that maldeployment of endoanchor implants may be overcome by careful preoperative planning to identify the apposition zone and to prevent deployment in a gap more than 2 mm between the aortic wall and endograft.
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