Outcomes of endosutured aneurysm repair with the Heli-FX EndoAnchor implants

Abstract

Objective

Endovascular aneurysm repair has gained field over open surgery for the treatment of abdominal aortic aneurysm. However, type Ia endoleak represents a common complication especially in hostile neck anatomy that is recently faced using endoanchors. We conducted a systematic review and meta-analysis to collect and analyse all the available comparative evidence on the outcomes of the endosuture aneurysm repair in patients with or without hostile neck in standard endovascular aneurysm repair.

Methods

The current meta-analysis was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All the prospective and retrospective studies reporting primary use of the Heli-FX EndoAnchor implants were considered eligible for inclusion in this study. The main study outcomes (technical success of endoanchor implantation, incidence of type Ia endoleak, aortic stent graft migration and the percentage of patients who presented regression or expansion of aneurysm sac throughout the follow-up) were subsequently expressed as proportions and 95% confidence intervals.

Results

Eight studies with a total of 968 patients were included in a pooled analysis. The technical success of the primary endoanchor fixation was 97.12% (95%CI: 92.98–99.67). During a mean six months follow-up period, a pooled rate of 6.23% (95%CI: 0.83–15.25) of the patients developed a persistent type Ia endoleak despite the primary implantation. Migration of the main graft was reported in five studies, in which a 0.26% (95%CI = 0.00–1.54) of the patients required an additional proximal aortic cuff. Regression of the aneurysm sac was observed at 68.82% (95%CI: 51.02–84.21). An expansion of the aneurysm sac was found in 1.93% (95%CI: 0.91–3.24) of the participants. The overall survival rate was 93.43% (95%CI: 89.97–96.29) at a mean six months follow-up period.

Conclusions

Endosuture aneurysm repair with the Heli-FX EndoAnchor implants seems to be technically feasible and safe either for prevention or for repair of intraoperative type Ia endoleak. Despite the primary implants of endoanchors, few cases of persistent type Ia endoleak and migration are still conspicuous. Long-term follow up is needed to determinate the role of this therapeutic option in the treatment of aortic aneurysms.

Keywords

Endoanchor EVAR abdominal aortic aneurysm Heli-FX EndoAnchor implants endosuture aneurysm repair

Introduction

Endovascular aneurysm repair (EVAR) has gained popularity over the last years against open surgery for the treatment of abdominal aortic aneurysms (AAAs). However, unfavourable morphology of the aneurysm and mainly adverse anatomic characteristics of the infrarenal aortic neck constitute the “Achilles heel” of the procedure.^1,2 Type Ia endoleak may complicate patients with hostile neck anatomy highlighting the anatomic limitations suggested by EVAR devices’ instructions for use (IFU).¹ However, despite anatomic limitations, a recent study revealed that 44.1% of EVAR procedures were performed outside device IFU, which might be the reason for the high rate of aneurysmal expansion of 41% at five years.³ As a result, it is still under consideration whether we should closely follow IFU guidelines or explore other potential means to address the persistent issue of durable sealing and fixation in unfavourable aortic neck.

Currently, Aptus Heli-FX EndoAnchor System (Medtronic Vascular, Santa Rosa, CA, USA) is the only device approved for clinical use to aid in endograft sealing and fixation, especially in circumstances of hostile aortic neck. It is designed to penetrate both the endograft fabric and aortic wall to ensure endograft fixation and seal in the infrarenal aortic neck during EVAR. Endoanchor implants are used prophylactically to prevent migration of the endograft or to treat intraoperative or late type Ia endoleaks in a therapeutic setting.^4,5

The objective of the present study was to collect and analyse all the available data regarding the use of endoanchors in AAA patients with hostile aortic neck and conduct a systematic review and meta-analysis of the literature.

Methods

Information sources

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used for this meta-analysis.⁶ The search was applied to MEDLINE (database provider PubMed, from 1966 to May 2012), EMBASE (database provider Ovid, from 1980 to May 2012), Google Scholar and Cochrane Central Register of Controlled Trials (May 2012). A snowball process in the reference lists of the eligible articles was performed after retrieval of the relevant articles from search of the databases.

Search methodology

We used the following search terms in all possible combinations: ‘endostaple’, ‘endoanchors’, ‘heli-fx’, ‘aptus’, ‘endovascular aortic repair’, ‘EVAR’, ‘aortic aneurysm’ and ‘evar’: a thorough search of the English-language literature published until July 2019 was performed to identify studies using to endoanchors during EVAR. The Newcastle–Ottava tool⁷ was applied to evaluate the methodologic quality of the studies. This scale was developed to assess the quality of studies using a ‘star system’ (maximum nine stars), in which a study is judged on three broad perspectives: (1) the selection of the study groups, (2) the comparability of the groups and (3) the ascertainment of outcome of interest.

Inclusion and exclusion criteria and data extraction

Studies reporting on primary use of endoanchors in patients undergoing 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 Ia endoleak. Unfavourable neck anatomy was defined as anatomical characteristics outside IFU for each endograft device used in the selected studies. More specifically, in the ANCHOR registry,⁸ unfavourable anatomy was defined as a neck with one or more of the following characteristics: neck length <10 mm, infrarenal aortic diameter ≥ 28 mm, neck angulation ≥ 60°, neck thrombus/calcium ≥ 2 mm average thickness or neck thrombus/calcium ≥ 180° of neck circumference. Patients were considered to have an unfavourable anatomy if one or more of the aforementioned criteria were present on preoperative computed tomography (CT) angiography scans. Migration was defined as any postimplantation movement or displacement of the stent graft in relation to the native aorta or renal arteries as documented on CT scans. Only studies with treatment of ≥10 patients were enrolled in the meta-analysis, while case reports, series with fewer than ten patients and reviews of the literature were excluded from the analysis. We also excluded studies, which referred to implantation of endoanchors, but they did not report outcome data. Duplicates were excluded, while in case of metachronous publications from the same surgical group, only the latest article or the article with the largest number of patients was included.

Data extracted from the eligible studies included the first author’s name, study year, total number of patients, number of male patients, type of aortic device, follow-up (months) inclusion and exclusion criteria and description of complications during follow-up. We also extracted the number of patients with outcomes of interest, which were described as early/late primary outcomes and late secondary outcomes. Early outcomes were defined as outcomes during the index procedure period (initial procedure in which Endoanchors were implanted), while outcomes during the follow-up period were defined as late. Early primary outcome included the technical success of endoanchors implantation while late primary outcomes included the following: incidence of type Ia endoleak, migration and the number of patients who presented regression or expansion of aneurysm sac throughout the follow-up period. Secondary outcome endpoints were defined the freedom of aneurysm-related reintervention, the rate of aneurysm rupture and the overall survival rate. Outcome criteria and definitions were based on recommended reporting standards for EVAR using endoanchors, published by ANCHOR registry.⁶

Statistical analysis

The number of patients with outcomes of interest were extracted for each of the eligible studies and was reported as the proportion of patients with the corresponding outcome among all patients with primary endoanchors implantation during EVAR. All values of the studied outcomes were subsequently expressed as proportions and 95% confidence intervals (95% CIs) and thereafter transformed into quantities according to the Freeman–Tukey variant of the arcsine square root transformed proportion. The pooled effect estimates were calculated as the back-transformation of the weighted mean of the transformed proportions, using Der Simonian–Laird weights of random effects model and expressed as % proportions. We used a formal statistical test for heterogeneity (I² test). The STATA statistical software v14 (Stata Corp LP, USA) was used for our analyses.

Results

Study characteristics

We identified 50 potentially eligible studies after a literature search. Review of the titles and abstracts evidenced that 21 articles were irrelevant at first screening stage. A total of 29 articles were further evaluated. Among them, 21 articles were also excluded at the second screening stage. Due to the numerous published studies related to the ANCHOR registry,⁸ we selected only the study with the mid-term results after primary implantation of the endoanchors, published by Jordan et al.⁵ Finally, eight articles^5,9–15 participated in the meta-analysis (Figure 1) corresponding to a total of 968 patients who underwent primary endoanchors implantation during standard EVAR. Median Newcastle–Ottawa score was 6 with a range of 5–6 (Supplementary Table 1).

Figure 1.

Study flow chart (PRISMA diagram).

Baseline study characteristics of the eight eligible studies included in the systematic review (four prospective and four retrospective studies) are presented in Table 1. The included studies were published from 2009 to 2019. Of the 968 patients included in our systematic review, 482 (59.2%) were males; Endoanchors were used in 742 (76.6%) patients for prophylaxis, while in 127 (13.1%) for treatment of an intraoperative type Ia endoleak. The mean number of endoanchors deployed per patient was four endoanchors in two studies and^14,15 five endoanchors in five studies^5,10–13 while only one study used six endoanchors.⁹ The mean imaging follow-up of the studies was six months. Anatomical neck characteristics of hostile neck were reported only in two studies^9–10 included 116 patients. Among these patients, crude rates (unadjusted for study’s weight) were 19.6% (18/92) for persistent type Ia Endoleak despite the primary implants, 18.1% (21/116) for type II endoleak during FU, while 0.86% (1/116) of these patients needed additional proximal aortic cuff due to migration of the graft. A zero aneurysm-related mortality was noted, with 5.2% (6/116) mortality not-related to the procedure. We did not record any aneurysm rupture, while re-intervention rate was 6.9% (8/116).

Table 1.

Baseline characteristics of patients among the studies.

Authors	Year	Type of study	Number of participants in each study (n)	Mean patients’ age (years)		Medical comorbidities/number of patients (n)										ASA class				Types and number of endografts used				Mean IMAGING FU (months)
						BMI	HPT	HPL	DM	Tobacco use	Cardiac disease	Pulmonary disease	Renal insufficiency	CVD	PAD	I	II	III	IV	Medtronic endurant	Cook Zenith	Gore excluder	Other endografts (InCraft/Vali ant/Aptus)
Valdivia et al.⁹	2019	PS	46	74	43	NR	40	29	10	13	24	19	4	NR	NR	NR	NR	46	NR	45	NR	NR	1	15
Arko et al.¹⁰	2019	RS	70	71.3	51	28.4	59	52	16	56	44	34	8	13	13	2	3	47	18	70	NR	NR	NR	12
Muhs et al.¹¹	2017	RS	198	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	53	11	35	0	24
Tassiopoulos et al.¹²	2017	RS	257	73	196	27.8	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR	NR
Jordan et al.¹¹	2015	RS	208	72	159	NR	172	149	41	NR	123	73	37	29	NR	3	14	147	44	101	30	72	5	14
Mehta et al.¹³	2014	PS	155	73	145	NR	NR	NR	NR	124	88	NR	9	17	31	NR	NR	NR	NR	NR	NR	NR	NR	41
Perdikides et al.¹⁴	2012	PS	13	73	13	NR	7	NR	1	NR	7	3	NR	NR	NR	13	NR	NR	NR	4	9	NR	NR	7
Deaton et al.¹⁵ (STAPLE-1) study	2009	PS	21	75	20	NR	15	NR	NR	19	23	5	3	2	2	NR	NR	NR	NR	NR	NR	NR	21	6
Overall	2009–2019		968	73,4	627		293	230	68	212	309	134	61	61	46	18	17	240	62	273	50	107	27	10

ASA: American Society of Anesthesiologists score; BMI: body mass index; HPT: hypertension; HPL: hyperlipidemia; DM: diabetes melitus; CVD: cerebro vascular diseases; PAD: peripheral arterial diseases; PS: prospective study; RS: retrospective study; NR: not reported; FU: follow-up.

Meta-analysis

The technical success for endoanchors deployment extracted by six studies^{5,9,10,13–15} was 97.12% (95%CI: 92.98–99.67) (Figure 2). All the studies defined technical success as successful implantation of endoanchors with adequate penetration of the aortic wall and absence of a type Ia endoleak at completion angiography. The incidence of type Ia endoleak after primary use of endoanchors was 6.23% (95%CI: 0.83–15.25) (Figure 3), and it was reported by five studies.^5,9–11,13 These endoleaks were detected on CT angiography during a mean follow-up period of six months (range: 17 ± 12.14 months). Migration of the main graft was reported in five studies^5,9,10,14,15 in which a 0.26% (95%CI = 0.00–1.54) of the patients required an additional proximal aortic cuff due to persistent type Ia endoleak (Figure 4). Data on regression or expansion of the aneurysm sac were extracted from six studies.^{5,9,11–13,15} Regression of the aneurysmal sac was estimated at 68.82% (95%CI: 51.02–84.21), while 1.93% (95%CI: 0.91–3.24) of the patients developed expansion of the sac (Figures 5 and 6).

Figure 2.

Forest plot presenting the meta-analysis of technical success. Event rates in the individual studies are presented as squares with 95% CIs presented as extending lines. The pooled event rate with its 95%CI is depicted as a diamond.

Figure 3.

Forest plot presenting the meta-analysis of Type Ia endoleak. Event rates in the individual studies are presented as squares with 95% CIs presented as extending lines. The pooled event rate with its 95%CI is depicted as a diamond.

Figure 4.

Forest plot presenting the meta-analysis of migration of the main graft and the need for additional proximal aortic cuff. Event rates in the individual studies are presented as squares with 95% CIs presented as extending lines. The pooled event rate with its 95%CI is depicted as a diamond.

Figure 5.

Forest plot presenting the meta-analysis of regression of aneurysmal sac. Event rates in the individual studies are presented as squares with 95% CIs presented as extending lines. The pooled event rate with its 95%CI is depicted as a diamond.

Figure 6.

Forest plot presenting the meta-analysis of expansion of aneurysmal sac. Event rates in the individual studies are presented as squares with 95% CIs presented as extending lines. The pooled event rate with its 95%CI is depicted as a diamond.

Data on the freedom of aneurysm-related reintervention at a mean 10 months follow-up period were extracted from four studies.^5,9,14,15 The pooled rate was 97.68% (95%CI: 95.17–99.44) (Supplementary Figure 1). No aneurysm rupture was recorded among four eligible studies^5,9,10,15 (Supplementary Figure 2). The overall survival during a mean 10 months follow-up period was 93.43% (95%CI: 89.97–96.29) (Supplementary Figure 3), and it was extracted by four studies.^9,10,13,14

Discussion

This meta-analysis derived from a comprehensive review of four prospective and four retrospective studies and provided pooled outcome rates for patients treated with endoanchors during standard EVAR. The technical success was high at 97%, indicating the applicability of method. Good preoperative planning, stringent anatomic guidelines for use of the Heli-FX device and the accuracy of the endostaples apposition may have led to these satisfactory results. Moreover, in our pooled analysis, persistent six-month type Ia endoleak was low, approximately 6% in patients who had undergone primary endoanchors implantation, while no significant aortic stent-graft migration was recorded. During follow up, we did not record any aneurysm-related rupture, highlighting the safety of the technique.

Adequate proximal sealing and fixation have been recognized as key elements in establishing long-term durability after EVAR. Endoleaks and migration may hamper the success of the procedure and may lead to high rates of late reinterventions and graft failure.¹¹ In a recently published meta-analysis evaluating data from the large multicenter randomized studies (ACE, OVER, DREAM and EVAR-1), type Ia endoleak was the second most common complication, for which 65.8% of the subjects required an early reintervention.¹⁶ Interestingly, even serious complications such as type I endoleak were not always corrected quickly, which may have contributed to the increasing aneurysm‐related mortality rate in the EVAR group at three or more years after aneurysm repair, highlighting the importance of type I endoleak correction in EVAR patients.

Despite these high rates of aneurysm-related complications and reinterventions, an increasing number of aneurysms with hostile neck anatomy have been treated with EVAR. Although, industrial companies providing endografts have proposed IFUs without the outward thinking of adopting adjunct technological measures, such as endoanchors, soon they have been implemented in clinical practice as adjunctive mechanism devised specifically to aid in endograft sealing and fixation. In challenging aortic necks, they are intended to provide better fixation and sealing between the endovascular grafts and the native aortic wall at the level of the proximal attachment site, with good assistance in the prevention and management of type Ia endoleaks and stent graft migration.

The ANCHOR registry¹¹ was used to examine whether prophylactic use of endoanchors contributed to improved outcomes after EVAR, using a propensity-matched cohort analysis. The authors found that freedom of type Ia endoleak was 97% in the ANCHOR and 94% in the control cohort group, respectively. Although, this study failed to demonstrate a significant difference in the rate of type Ia endoleak, the rate of sac regression in the subjects treated with endoanchors was significantly higher at 81%, compared to controls. In our analysis, pooling together data from all published studies, endoleak rate was estimated at 6%, while regression of the aneurysmal sac was estimated at 69%. Prophylactic implantation of endoanchors may temper the inhibiting effect of intrasac thrombus, promoting later sac regression.¹¹

The prevention of endograft migration is the second main indication for the use of endoanchors. An estimated migration rate from 0.7 to 6.3% without the use of endoanchors has been recorded after standard EVAR. In contrast, a very low rate of graft migration (0.26%) was detected in our meta-analysis with the use of endoanchors, pointing to enhanced proximal neck fixation and seal zone competency and indicating the effectiveness of the technique. This extremely low migration rate with the use of Aptus Heli-FX system is mainly attributed to the endoanchors which penetrate well into the aortic wall in a similar manner to a traditional hand-sewn surgical anastomosis. Interestingly, in cadaveric aortic studies, equivalent to or greater forces were required to displace an endograft when endoanchors were deployed compared to a surgical anastomosis.⁵ However, endograft migration without endoanchor dislocation might happen, and possible reasons include inability of endoanchors to fully penetrate the aortic wall or penetration into aortic neck thrombus alone or dislocation from the aortic wall over time or even elongation of the aortic neck. For that reason, four to six endoanchors are usually recommended during implantation.¹³

Our analysis also showed that almost 98% of the patients were free from reintervention during follow-up, highlighting the durability of the endoanchors technique. Misdeployment of the endoanchors at the end of the procedure observed in few cases due to the heavily calcified aorta, and it 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, highlighting the utility of the preoperative planning to reach adequate Endoanchor penetration.

There are several limitations of this study, mainly mirroring the limitations of the included studies. First, the limited follow-up period of the eligible studies in our meta-analysis precluded a long-term assessment of the utility of the endoanchors as a definite prophylactic adjunct. The ANCHOR registry is ongoing and has recruited >800 patients so far with a target to be 1200 participants (https://clinicaltrials.gov/ct2/show/NCT01534819). The end of this registry should shed lights in this topic, and some of the queries raised will be resolved. Unfortunately, STAPLE-1, a historical trial, which took place few years ago, is no longer used, and no additional data regarding the long-term follow-up and assessment of endoanchors are available. Second, the lack of randomized trials also limits the results to real-world practice. Additionally, differences in definitions and follow-up imaging may introduce heterogeneity in pooling data together. Moreover, no anatomically based evaluation of the treated necks existed. Only, few reports had core lab evaluation of the CT imaging to help define the neck anatomy and correlate those findings with success. Information about the co-existence of type II endoleaks, which may have led to persistence of low flow type Ia endoleaks, was also missing.

Conclusion

Endoanchors seem to be a useful adjunct to the growing EVAR armamentarium for at least in the short-term (six-month) follow-up period. Their fixation seems to be safely used in the prevention and treatment of type Ia endoleaks with good results of sac shrinkage and diameter reduction. Long-term results and randomized control studies are required.

Supplemental Material

sj-pdf-1-vas-10.1177_1708538120923417 - Supplemental material for Outcomes of endosutured aneurysm repair with the Heli-FX EndoAnchor implants

Supplemental material, sj-pdf-1-vas-10.1177_1708538120923417 for Outcomes of endosutured aneurysm repair with the Heli-FX EndoAnchor implants by Georgios Karaolanis, Constantine N Antonopoulos, Stylianos Koutsias, George A Antoniou, Efthymios Beropoulis, Giovanni Torsello, Gergana T Taneva and Konstantinos P Donas in Vascular

Supplemental Material

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Supplemental material, sj-pdf-2-vas-10.1177_1708538120923417 for Outcomes of endosutured aneurysm repair with the Heli-FX EndoAnchor implants by Georgios Karaolanis, Constantine N Antonopoulos, Stylianos Koutsias, George A Antoniou, Efthymios Beropoulis, Giovanni Torsello, Gergana T Taneva and Konstantinos P Donas in Vascular

Supplemental Material

sj-pdf-3-vas-10.1177_1708538120923417 - Supplemental material for Outcomes of endosutured aneurysm repair with the Heli-FX EndoAnchor implants

Supplemental material, sj-pdf-3-vas-10.1177_1708538120923417 for Outcomes of endosutured aneurysm repair with the Heli-FX EndoAnchor implants by Georgios Karaolanis, Constantine N Antonopoulos, Stylianos Koutsias, George A Antoniou, Efthymios Beropoulis, Giovanni Torsello, Gergana T Taneva and Konstantinos P Donas in Vascular

Supplemental Material

sj-pdf-4-vas-10.1177_1708538120923417 - Supplemental material for Outcomes of endosutured aneurysm repair with the Heli-FX EndoAnchor implants

Supplemental material, sj-pdf-4-vas-10.1177_1708538120923417 for Outcomes of endosutured aneurysm repair with the Heli-FX EndoAnchor implants by Georgios Karaolanis, Constantine N Antonopoulos, Stylianos Koutsias, George A Antoniou, Efthymios Beropoulis, Giovanni Torsello, Gergana T Taneva and Konstantinos P Donas in Vascular

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Georgios Karaolanis

Constantine N Antonopoulos

Efthymios Beropoulis

Gergana T Taneva

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