Multicentre experience with an iliac fenestrated device

Abstract

 

OBJECTIVES

The aim of this study was to present a multicentre experience of technical results and mid-term follow-up using a custom-made iliac fenestrated device (Terumo Aortic, Inchinnan, Renfrewshire, UK) for the treatment of iliac aneurysms and endoleaks.

METHODS

A multicentre retrospective evaluation of 22 patients (3–12 per institution) with either an iliac artery aneurysm or endoleak treated with an iliac fenestrated device was performed. Data were gathered from 3 departments of vascular and endovascular surgery at 3 European institutions.

RESULTS

Ten of the included patients (45.5%) were treated for an endoleak and 12 had aorto-iliac aneurysms (54.5%). Two patients underwent bilateral fenestrated device implantation for a total of 24 devices included in this analysis. Primary technical success was 91.7% (22 of 24 implanted devices). One of the 24 internal iliac arteries could not be cannulated and was covered (primary assisted technical success rate 95.8%) and 1 patient required a relining of the stent graft due to a mid-grade stenosis opposite the internal iliac artery fenestration. Survival at the last available follow-up (mean 15.2 ± 12.0 months, range 0.5–36.6 months) was 90.9%.

CONCLUSIONS

The present investigation adds to a growing body of literature on custom-made endografts and their usefulness in achieving endovascular repair without compromising blood flow via important arterial branch vessels, such as the internal iliac artery. It presents encouraging technical and mid-term follow-up data from consecutive patients treated for iliac aneurysms or endoleaks using this custom-made device. The technique may help avoid adverse sequelae associated to a coil-and-cover approach when iliac branch devices are not feasible.

INTRODUCTION

The utilization of covered stent grafts in endovascular aneurysm repair demands special considerations for achieving a sufficient sealing zone to exclude pathologies, while also avoiding the coverage of important branch vessels. Fenestrated endovascular aortic repair (fenestrated EVAR) has been associated with good technical outcomes and high target vessel patency when treating pararenal aortic pathologies, and when used to treat type Ia endoleak after EVAR [1, 2]. For the iliac arteries, iliac branch devices (IBDs), including the ZBIS Zenith (Cook, Bloomington, IN, USA), the Gore Excluder (W. L. Gore & Associates, Inc., Elkton, MD, USA) and the Jotec E-liac (JOTEC, Hechingen, Germany) systems, are available to treat a range of anatomic configurations, which may not provide adequate distal sealing zones within the common iliac arteries for standard EVAR [3]. Clinical results for these devices have been encouraging, with good technical success rates and outcomes reported [4–6].

Preserving blood flow via the internal iliac artery (IIA) may help to avoid complications ranging from buttock claudication, or erectile dysfunction [7], to potentially debilitating conditions, such as spinal cord ischaemia or colonic necrosis. Reinterventions due to the progression of disease or development of a type Ib endoleak may be especially challenging. Certain anatomical situations, including the presence of an in situ iliac limb from prior EVAR, may impede repair using off-the-shelf devices without disruption of blood flow to the IIA. To avoid a coil-and-cover approach (and associated adverse sequelae), custom-made solutions may be a feasible alternative in appropriate patients. The current multicentre investigation presents technical results and mid-term clinical follow-up data of a custom-made iliac fenestrated device (IFD; Anaconda Iliac Fenestrated Device, IFD, Terumo Aortic, Inchinnan, Renfrewshire, UK) used to treat patients with iliac aneurysms or endoleak after EVAR.

MATERIALS AND METHODS

Study design

The present investigation was approved by the appropriate ethical review board. A retrospective analysis at 3 European centres was performed to identify patients who were treated with an IFD (Fig. 1). The first implantation was performed in 2017 and all implantations taking place until December of 2020 were included. Electronic and physical medical records of 22 consecutive patients from the 3 participating institutions were accessed to retrospectively assess and report patient demographics, the indication for surgery, as well as perioperative data, and technical and clinical results.

Figure 1:

Iliac fenestrated device. Note 4 radio-opaque markers around the fenestration and an additional marker at the top of the fenestration. No supporting stents are present around the fenestration.

Applied technique for iliac fenestrated device implantation

The IFDs were custom-made based on 1-mm slice thickness computed tomography angiography studies. The device was designed with an appropriate oversizing of 10–20% and often featured a taper to account for possibly different landing zones in the common iliac artery or in situ endograft limb proximally, and external iliac artery distally. As is the case with fenestrated EVAR in the pararenal setting, the device is intended for scenarios where the fenestration will be in proximity to the target vessel origin. For use of the IFD, a minimum of ∼12 mm of flow lumen are required opposite the IIA origin to provide sufficient space for positioning and flaring of the connecting stent graft.

The applied technique of IFD implantation has recently been published in the form of a case report [8] and will additionally be outlined here. Intraoperative imaging from a representative case is provided by Fig. 2. The device is delivered via a groin access to the common femoral artery. This can be achieved via percutaneous or open access. An angiogram is obtained to locate and mark the origin of the IIA. Radiopaque markers around the fenestration are then used to align the fenestration with the IIA origin. Once the fenestrated device has correctly been aligned, it can be deployed in the same fashion as a regular EVAR limb extension. The delivery system is then retrieved and removed, freeing up the original arterial access to be used for the subsequent cannulation (of the fenestration and IIA) using a hydrophilic wire. A steerable 7-Fr sheath was used increasingly over the study period at all participating centres. This facilitates cannulation and connection of the fenestration and target vessel with an appropriately sized balloon expandable stent graft. The Atrium V12 stent graft (Maquet Getinge Group, Inc., Berlin, Germany) was used as the connecting stent graft of choice at all 3 participating centres and was delivered over a J-tip Rosen guide-wire (Cook). The connecting stent graft is flared adequately (in most cases using an 8 or 10 mm × 2 cm flaring balloon). A completion angiogram is then performed. For standalone IFD procedures (no concomitant aortic endograft implanted), the entire reconstruction can be performed via the ipsilateral groin, without the need for a crossover, transbrachial or other additional arterial access site (also includes patients with history of prior EVAR and in situ endograft).

Figure 2:

Intraoperative imaging from a representative case of iliac fenestrated device implantation. (A) Intraoperative angiography allows identification of the target vessel (internal iliac artery) to deploy the fenestrated device in correct orientation. (B) Cannulation and length measurement are performed via the fenestration. (C) Completed deployment and flaring of a connecting stent graft and (D) completion angiogram.

End points

The primary end points are survival, technical success, connecting stent graft patency and reintervention rates. Secondary end points include endoleaks and other complications, as well as duration of surgery, and amount of contrast medium required. Success rates were defined according to published reporting standards of the Society for Vascular Surgery [9].

Statistical analysis

Descriptive statistics were calculated in terms of means and standard deviations for continuous variables and frequencies and percentages for categorical ones. Kaplan–Meier survival curves were calculated and are shown for the primary end points survival, reinterventions and connecting stent graft patency. Survival and reintervention rates are considered using the number of treated patients (n = 22) as the denominator, whereas technical success and patency rates refer to the number of implanted fenestrated devices (n = 24). All statistical analyses were performed using SPSS 21.0 software (IBM Corp., Armonk, NY, USA).

RESULTS

Baseline results (demographic patient data and surgical treatment plan)

All procedures were carried out between 2017 and 2020 and the mean age at surgery was 73.8 ± 8.6 years (range 55–87 years). Twenty of the included patients were male (90.9%) and 2 were female (9.1%). The indications for surgery were aorto-iliac aneurysms (12 patients or 54.5%) or endoleaks (10 patients or 45.5%). Among the treated endoleaks, 2 were classified as type III, one of which occurred in a patient who had undergone EVAR using a left-sided IBD (Fig. 3). The remaining treated endoleaks were type Ib after prior EVAR (8 of 22 patients; 36.4%). Abundant comorbidities were arterial hypertension (17/22; 77.3%), a history of smoking (14/22; 63.6%) and coronary artery disease (9/22; 40.9%). Six patients (27.3%) presented a history of malignant disease (prostate cancer n = 1, bronchial carcinoma n = 3 and melanoma n = 1). Chronic renal insufficiency was recorded for 6 patients (27.3%). All included patients were asymptomatic and iliac pathologies were detected during routine follow-up, either for a known aneurysm or after EVAR. Ten patients were post-EVAR and 9 patients received an EVAR during the same procedure during which the IFD was implanted. Two of 22 patients underwent bilateral IFD implantation for a total of 24 implanted IFDs. Risk factors for adverse sequelae of IIA coverage were considered to include compromised blood flow via the contralateral IIA or relevant coverage of part of the aorta following prior endovascular procedures (Fig. 4). Use of a steerable sheath was documented for a majority of patients (14 of 22 procedures; 63.6%).

Figure 3:

Three-dimensional reconstructions from computed tomography angiography (view from posteriorly) show (A) contrast within the aneurysm sack due to type III endoleak originating from connection of an endovascular aortic repair device to an iliac branch device within the left iliac artery and (B) resolution of the endoleak following treatment using a fenestrated iliac device. (C) Intraoperative fluoroscopy displays alignment of the fenestration (arrow) with the origin of the iliac branch before deployment of the graft during the procedure.

Figure 4:

Thoraco-abdominal endovascular aortic repair and iliac fenestrated device utilization in the left iliac artery in a setting of contralateral internal iliac artery occlusion (as seen on 3-dimensional reconstruction from postoperative computed tomography angiography).

Survival, technical success, reinterventions and target artery patency

Primary technical success was 91.7% (22 of 24 implanted devices). Assisted primary technical success (after relining with a self-expandable stent to treat mid-grade, asymptomatic postoperative stenosis opposite the fenestration in 1 patient) was 95.8% (23 of 24 implanted devices). One of the 24 treated internal iliac arteries could not be cannulated and had to be covered during the index procedure. The remaining target arteries showed good patency until last follow-up, with no additional occlusions detected, and overall survival at the mean of last available follow-up of 15.2 ± 12.0 months (range 0.5–36.6 months) was 90.9% (see Fig. 5 for relevant Kaplan–Meier curves and calculations). Thirty-day mortality amounted to 4.5% (1 mortality at postoperative day 16 in a patient after extensive thoraco-abdominal aortic aneurysm repair and use of an IFD). The second mortality occurred 13 months postoperatively (cause of death: acute myeloid leukaemia). One surgical site infection was observed (1 of 22 patients; 4.5%) after open groin access. Table 1 provides further information on secondary end points. Table 2 characterizes the endoleaks encountered after IFD implantation in the current series.

Figure 5:

Kaplan–Meier calculations and curves depicting survival (A), reinterventions (B) and connecting stent graft patency (C). CI: confidence interval; IIA: internal iliac artery; SE.

Table 1:

Demographic and anatomical patient characteristics and perioperative data

Mean age at surgery ± SD (range) (years)	Gender	Indication for IFD use
73.8 ± 8.6 (55–87)	2 female (9.1%): 20 male (90.9%)	Aneurysm: 12 (54.5%)
		Endoleak: 10 (45.5%; 8 type I and 2 type III)
Mean duration of surgery ± SD (range) (min)	Mean amount of contrast medium required ± SD (range) (ml)	Reintervention rate
205.6 ± 75.5 (80–377)	170.0 ± 65.5 (90–300)	13.6% (3 of 22 patients; 2 revision-stentings; 1 thrombectomy)

IFD: iliac fenestrated device; SD: standard deviation.

Table 2:

Characterization of observed endoleaks during follow-up

Endoleak type	Frequency	Timepoint	Consequence
I	1/24 implanted IFDs (4.2%)	At 9 months	Reintervention with IIA stent graft implantation
II	1/24 implanted IFDs (4.2%)	At last follow-up of 31 months	Under surveillance (no aneurysm expansion)
III	None	NA	NA

IFD: iliac fenestrated device; IIA: internal iliac artery; NA: not applicable.

DISCUSSION

Technical and mid-term clinical results with a custom-made fenestrated iliac device were encouraging in the current series. Experience from 22 consecutive patients treated with a total of 24 IFDs at 3 European centres is conveyed. Blood flow via the IIA was maintained in all but one of the enrolled cases (patient with IIA loss remained asymptomatic). Mid-term follow-up data show acceptable clinical results with low mortality and reintervention rates. A majority of patients (19 of 22; 86.4%) underwent concomitant pararenal or thoraco-abdominal aneurysm repair or were already post-EVAR. The complexity of included cases is also represented in a large range of surgery durations (up to 377 min) and one case of perioperative mortality. Given that the IIAs salvaged through the use of an IFD in the current series would inherently have been lost if coiled and covered, these results support the idea of a custom-made solution to have its merit for IIA preservation when the use of IBDs is not feasible.

From a technical standpoint, the device is relatively simple to handle, as it can be completely deployed before cannulations are attempted, thereby allowing the ipsilateral arterial access in the groin to be used for the connection of the target artery. Use of a steerable sheath can further facilitate cannulation and connection of the fenestration to the IIA via the groin access. Crossover manoeuvers (potentially requiring an ‘up-and-over’ [10] approach if attempted in a patient post-EVAR) or transbrachial arterial accesses [11] are usually not required for IIA connection to an IFD.

Fenestrated and branched techniques are popular for the treatment of pararenal and thoraco-abdominal pathologies and often rely on a custom-made graft, especially in fenestrated EVAR [12]. An increasing experience with complex endovascular aneurysm repair has improved clinical results [13–15] and branched techniques are also used within the iliac arteries with high technical success [4–6]. Coiling and coverage of the IIA, on the other hand, while an accepted method [16], can result in buttock claudication and considerable morbidity. In the most unfortunate of cases, loss of IIA blood flow may result in debilitating, possibly life-threatening conditions, such as paraplegia or colonic necrosis. The practical guideline of the ESVS therefore recommends at least 1 IIA be preserved [17, 18]. Open repair [16] or off-the-shelf IBD solutions may be feasible in some but not all patients and IFDs may then offer an additional option.

Limitations

Limitations of the current study are its retrospective design and a relatively small sample size. The multicentre design was chosen to account for the fact that IFD use is rather infrequent. Use of a custom-made IFD (with a production time of ∼3 weeks) is restricted to the elective setting and for the most part reserved for patients in whom no off-the-shelf alternative is feasible. With that in mind, the current study aims to supplement our knowledge regarding the feasibility of custom-made devices by adding a multicentre clinical experience from an iliac artery setting.

CONCLUSION

Technical results and mid-term follow-up data from the use of a custom-made fenestrated device in an iliac artery setting are encouraging. The custom-made IFD provides a viable option for some cases of iliac artery pathology in which anatomical limitations to off-the-shelf solutions apply. It may be particularly useful in cases of type Ib and type III endoleaks where space may be insufficient to accommodate the branch of an IBD. The reliance of the presented technique on a custom-made device limits its feasibility in an acute setting, where IBDs, open repair or covering of the IIA ostium may be among viable options.

Conflict of interest: While the manuscript remains unbiased in its interpretations, authors Fadi Taher, Stephan Langer, Juergen Falkensammer, Miriam Kliewer, Afshin Assadian and Alexander Stehr have all received honoraria for consulting or teaching engagements with the manufacturer (Terumo Aortic) of the device assessed within the study. All other authors declared no conflict of interest.

Author contributions

Fadi Taher: Conceptualization; Data curation; Investigation; Methodology; Software; Writing—original draft. Stephan Langer: Data curation; Investigation; Project administration; Supervision; Validation; Writing—review & editing. Juergen Falkensammer: Conceptualization; Data curation; Formal analysis; Investigation; Methodology; Software; Validation; Visualization; Writing—review & editing. Markus Plimon: Data curation; Investigation; Software; Visualization; Writing—review & editing. Miriam Kliewer: Data curation; Formal analysis; Investigation; Validation; Visualization; Writing—review & editing. Corinna Walter: Conceptualization; Data curation; Formal analysis; Investigation; Methodology; Software; Writing—review & editing. Afshin Assadian: Conceptualization; Data curation; Formal analysis; Investigation; Methodology; Project administration; Resources; Software; Supervision; Validation; Visualization; Writing—review & editing. Alexander Stehr: Data curation; Formal analysis; Investigation; Resources; Software; Supervision; Validation; Visualization; Writing—review & editing.

Reviewer information

Interactive CardioVascular and Thoracic Surgery thanks Roman Gottardi, Naoyuki Kimura, Mario Giovanni Gerardo D'Oria and the other, anonymous reviewer(s) for their contribution to the peer review process of this article.

ABBREVIATIONS

EVAR

Endovascular aortic repair

IBD

Iliac branch device

IFD

Iliac fenestrated device

IIA

Internal iliac artery