Migration of fenestrated aortic stent grafts

Risks and benefits of renal artery stenting in fibromuscular dysplasia: Lessons from the ARCADIA-POL study

INTRODUCTION

Although renal stenting is the standard revascularization method for atherosclerotic renal artery stenosis (RAS) (FMD-RAS), stenting in fibromuscular dysplasia (FMD) RAS is usually limited to periprocedural complications of angioplasty and primary arterial dissection. The main aim of the study was to retrospectively analyze the immediate and long-term results of renal stenting versus angioplasty in patients with FMD.

METHODS

Of 343 patients in the ARCADIA-POL registry, 58 patients underwent percutaneous treatment due to FMD-RAS (in 70 arteries). Percutaneous transluminal renal angioplasty (PTRA) was performed as an initial treatment in 61 arteries (PTRA-group), whereas primary stenting was undertaken in nine arteries (stent-group). Stent-related complications were defined as: in-stent restenosis > 50% (ISR); stent fracture; under-expansion; or migration.

RESULTS

In the PTRA-group, the initial restenosis rate was 50.8%. A second procedure was then performed in 22 arteries: re-PTRA (12 arteries) or stenting (10 arteries). The incidence of recurrent restenosis after re-PTRA was 41.7%. Complications occurred in seven of 10 (70%) arteries secondarily treated by stenting: two with under-expansion and five with ISR. In the stent-group, stent under-expansion occurred in one case (11.1%) and ISR in three of nine stents (33.3%). In combined analysis of stented arteries, either primarily or secondarily, stent-related complications occurred in 11/19 stenting procedures (57.9%): three due to under-expansion and eight due to ISRs. Finally, despite several revascularization attempts, four of 19 (21%) stented arteries were totally occluded and one was significantly stenosed at follow-up imaging.

CONCLUSION

Our study indicates that renal stenting in FMD-RAS may carry a high risk of late complications, including stent occlusion. Further observational data from large-scale registries are required.

Editor's Choice - Single Centre Midterm Experience with Primary Fenestrated Endovascular Aortic Aneurysm Repair for Short Neck, Juxtarenal, and Suprarenal Aneurysms

OBJECTIVE

The use of fenestrated stent grafts to treat short neck, juxta- and suprarenal aortic aneurysms is increasing worldwide, but midterm outcome reports are scarce. This study aimed to report peri-operative results and midterm outcomes after five years from a single centre.

METHODS

Patients treated with primary fenestrated endovascular aortic aneurysm repair (FEVAR) for short neck, juxta- or suprarenal aortic aneurysms within the period January 2010 to May 2020 with follow up in the centre were included. Early (technical success, operative mortality, spinal cord ischaemia) and five year outcomes (cumulative survival, freedom from aortic related death, target vessel patency, target vessel instability [TVI], re-interventions) were analysed.

RESULTS

A total of 349 patients (313 male, mean age 72.3 ± 7.7 years) were included in the study. Technical success was 98% (342/349). The thirty day mortality rate was 0.9% (3/349). Estimated survival at five years was 69.3 ± 3.1%. Freedom from aneurysm related death at five years was 98.8% ± 0.7%. Estimated target vessel patency at five years was 98.7 ± 0.4%. Estimated freedom from TVI at five years was 97.2 ± 0.6%. Estimated freedom from re-intervention at five years was 86.5 ± 2.3%. Survival did not differ significantly between patients with and without re-interventions (p = .088).

CONCLUSION

Midterm results of FEVAR remain good as indicated by sustained target vessel patency and low aortic related mortality rates. An important proportion of patients require re-interventions, which do not have a negative impact on midterm survival.

The effect of stent graft curvature on the hemodynamic displacement force after abdominal aortic aneurysm endovascular repair

Endovascular aortic aneurysm repair is a minimally invasive procedure with low mortality and morbidity. Clinical studies have revealed that a displacement force (DF) can cause stent graft (SG) migration in some circumstances requiring repeated intervention. This study aims to determine the relationship between the SG curvature and the calculated DF from four patient-specific computational fluid dynamics models. The SG's curvature was defined according to the centrelines of the implanted SG's branches. The centrelines were defined as either intersecting or separated lines. The centreline curvature (CLC) metrics were calculated based on the local curvature radii and the distances from the centrelines of idealized straight branches. The average CLC value and average variation were calculated to represent the entire graft's curvature. These CLC calculations were compared, and the method that gave the best correlation to the calculated DF was found. The optimal correlation is obtained from calculating the CLC average variation using separated centrelines and distance from straight lines, with an R² = 0.89. Understanding the relationship between vascular morphology and DF can help identify at-risk patients before the procedure. In these cases, we can provide appropriate treatment and follow up with the patient to prevent future failure.

Proximal Seal Dilatation following Fenestrated Endovascular Repair for Complex Abdominal Aortic Aneurysms

OBJECTIVES

Although Proximal neck dilatation following infrarenal endovascular aneurysm repair (EVAR) is common and is associated with proximal graft failure, little is known about sealing zone dilatation and its clinical relevance following fenestrated EVAR (FEVAR). We studied proximal seal dilatation (PSD) dynamics following FEVAR and assessed its clinical significance.

METHODS

We included all consecutive patients treated for a juxta-/supra-renal aneurysm with fenestrated EVAR using the Zenith Fenestrated Endovascular Graft (Cook Medical, Bloomington, Ind) from 2008 to 2018 in two large teaching hospitals in the Netherlands. The primary outcome was PSD over time and was determined using a linear mixed-effects model. Secondary outcomes included associations for early PSD and difference in aortic dilatation at the level of the covered-stent compared to the bare-stent. Proximal seal related adverse events were also obtained.

RESULTS

Our cohort included 84 patients with a median CTA follow-up time of 24.5 months [IQR 17-42]. Maximum aneurysm-diameter was 60.1 mm (IQR 56.9-67.2). Mean proximal seal diameter at baseline was 26.2 mm (±2.8), mean stent oversizing was 20.1% (±9.1), and mean proximal seal length was 29.5 mm (±11.7). Proximal seal dilatation of 1.7 mm (95%CI:1.4-2.1) was found in the first year, decelerating thereafter (2^nd-year: 0.9mm/year [95%CI:0.7-1.1]). Over 10% PSD at one year occurred in 22 patients (27%) and was associated with stent-graft oversizing (OR: 1.1 [95%CI:1.03-1.2], p=.008) and a lower number of target vessels (four fenestrations/ref two fenestrations: OR: 0.13 [95%CI:0.02-0.74], p=.029). At last available imaging, dilatation difference was higher at the level of the covered stent compared with the bare stent (3.0mm [IQR 1.3-5.1] vs. 1.6mm [IQR 0.8-2.5], p<.001). During the study period, only one patient (1.2%) developed a proximal seal related-adverse event (type-IA endoleak).

CONCLUSION

PSD is present following FEVAR, occurring at a faster rate in the first year and subsequently decelerating thereafter, similarly to neck dilatation after standard infrarenal EVAR. Although its clinical implication seems to remain limited in the first years following implantation, further research is required to assess the effect of PSD on long-term FEVAR outcomes.

Long-term Outcomes after FEVAR for Juxtarenal Aortic Aneurysm

OBJECTIVE

Fenestrated endovascular aortic repair (FEVAR) for juxtarenal aortic aneurysm (jAAA) disease is safe and effective with good short- and mid-term outcomes. Durability issues focus mainly on proximal and distal seal as well as target vessel (TV) instability, and long-term data is scarce. In previous publications we have reported short-term outcomes after FEVAR while comparing early- and late-experience patient groups, as well as long-term results for the early cohort. In this series we provide long-term outcome in the late experience cohort treated with FEVAR in Vascular Center Malmö.

METHODS

Consecutive patients treated in Vascular Center Malmö with FEVAR for jAAA between 2007 and 2011 were included. Data was collected retrospectively from medical- and imaging records. Follow up consisted of a clinical examination 1 month post-operatively, and computed tomography angiography combined with plain abdominal X-ray at 1 and 12 months, and annually thereafter. Primary endpoints were TV instability, reinterventions and survival. Changes in aneurysm diameter and renal function as well as endoleaks were also analyzed.

RESULTS

94 patients were treated. Median follow-up time was 89 (range 0-152) months. 280 fenestrations or scallops were employed of which 205 were stented. Technical success was 89.4%. Primary TV patency was 94% ± 1 % at 1year, 90% ± 2% at 3 years and 89% ± 2% at 5 years. 37 (39.4%) patients needed a total of 70 reinterventions and mean time to first reintervention was 21 ± 3.97 months. 5 (5.3%) patients died of aneurysm related causes and overall survival was 95.7% ± 2.1% at 1 year, 87.1% ± 3.5% at 3 years and 71.0 ± 4.7% at 5 years. A stable or decreasing aortic diameter after treatment was seen in 91% of cases. Mean glomerular filtration rate (GFR) fell from 59.2 ± 14.9 ml/min/1.73m² pre-operatively to 50.0 ± 18.6 ml/min/1.73 m² at end of follow-up.

CONCLUSION

Long-term results after treatment of jAAA with FEVAR remain good and the treatment is safe and effective. Although the need for reintervention remains high, long-term renal function and survival support the use of FEVAR as a valid treatment option for jAAA disease.

Aortic endograft and bridging stent-graft remodeling after branched endovascular aortic repair

OBJECTIVES

The results of branched endovascular repair of thoracoabdominal aneurysms are mainly dependent on durability of the graft used. The purpose of this study was to evaluate postoperative aortic main body and bridging stent-graft remodeling, and their impact on bridging stent-graft instability at one year.

METHODS

Computed tomoangiographies of 43 patients (43 aortic main body mated with 171 bridging stent-grafts) were analyzed before and after branched endovascular repair as well as after a follow-up of 12 months. Primary endpoint was aortic main body remodeling (migration >5 mm, shortening >5 mm, scoliosis >5° or lordosis >5°). Shortening was defined as a reduced length in the long axis, scoliosis as left-right curvature, and lordosis as antero-posterior curvature. Aortic main body remodeling, aneurysm sac changes, and bridging stent-graft tortuosity were evaluated to study their correlations and the impact on the bridging stent-graft instability.

RESULTS

At 12 months, aortic main body remodeling was observed in 72% of the cases, migration in 39.5% (mean 5.21 mm), shortening in 41.9% (mean 5.79 mm), scoliosis in 58.1%, (mean 10.10°), lordosis in 44.2% (mean 5.78°). Migration, shortening, and scoliosis were more frequent in patients with larger aneurysms (p = .005), while scoliosis was significantly more frequent in type II thoracoabdominal aneurysm (p = .019). Aortic main body remodeling was significantly associated to bridging stent-graft remodeling (r: 0.3-0.48). The bridging stent-graft instability rate was 9.3%. Despite a trend toward significance (p = .07), none of the evaluated aortic main body and bridging stent-graft changes were associated with bridging stent-graft instability at 12 months.

CONCLUSIONS

Aortic main body remodeling is frequent especially in large and extended thoracoabdominal aneurysm aneurysms. Aortic main body and bridging stent-graft remodeling was significantly correlated. While these geometric changes had no significant impact on bridging stent-graft instability at one year, a close long-term follow-up after branched endovascular repair could predict bridging stent-graft failures.

An External Iliac Artery Pseudoaneurysm Resulting From Stent Graft Migration

The case of an 80-year-old male with claudication of his left foot who was referred to our hospital for evaluation and treatment. Computed tomography (CT) angiography revealed occlusion of left common and external iliac (EIA) arteries. Recanalization of the EIA lesion under intravascular ultrasound (IVUS) guidance and placement of 2 stent grafts was completed successfully. Nine months later, 27 × 29 mm pseudoaneurysm of the left EIA was identified that appeared to have developed secondary to migration of the original stent graft. A new stent graft was placed.

Bridging stent grafts in fenestrated and branched endovascular aortic repair: current practice and possible complications

Fenestrated and branched endovascular aortic repair (F/B-EVAR) is associated with a high degree of technical and clinical success. Despite this, studies have also reported high reintervention rates, and these are often related to the bridging stent grafts. Often new devices appear on the market before they have been tested in the bridging stent graft position. This review aims to assess the current literature on bridging stent grafts and discuss complications, illustrated by case reports. Complications reported with bridging stent grafts include; endoleak, kink, fracture, migration, occlusion, stenosis and perforation. Some known risk factors for bridging stent occlusions are renal artery stent grafts vs. SMA and celiac artery stent grafts. Some device specific complications have also been reported such as type IIIc endoleak with the Lifestream stent graft (Bard Peripheral Vascular, Tempe, AZ, USA) fractures and type IIId endoleaks with the 1st generation of Begraft (BentleyInnoMed, Hechingen, Germany). In addition, this review also discusses some newer devices with possible relation to complications such as stenosis and target vessel perforation. In conclusion, bridging stent grafts in fenestrated and branched aortic repair have a good midterm patency. Despite this, remaining issues are often related to the bridging stent grafts. Thorough follow-up and attention are needed, especially when new devices are introduced. The endovascular community should work towards a common global feedback system.

Stent Frame Movement Following Endovascular Aneurysm Sealing in the Abdominal Aorta

Purpose: To investigate the incidence and extent of stent frame movement after endovascular aneurysm sealing (EVAS) in the abdominal aorta and its relationships to aneurysm growth and the instructions for use (IFU) of the Nellix endograft. Methods: A retrospective single-center study was conducted to review the clinical data and computed tomography (CT) images of 75 patients (mean age 76±7.6 years; 57 men) who underwent infrarenal EVAS and had a minimum 1-year follow-up. The first postoperative CT scan at 1 month and the subsequent scans were used to measure the distances between the proximal end of the stent frames and a reference visceral vessel using a previously validated technique. Device migration was based on the Society of Vascular Surgery definition of >10-mm downward movement of either Nellix stent frame in the proximal landing zone; a more conservative proximal displacement measure (downward movement ⩾4 mm) was also recorded. Patients were categorized according to adherence to the old (2013) or new (2016) Nellix IFU. Aneurysm diameter was measured for each scan; a change ⩾5 mm was deemed indicative of aneurysm growth. Results: Over a median follow-up of 24 months (range 12–48), proximal displacement ⩾4 mm occurred in 42 (56%) patients and migration >10 mm in 16 (21%), with similar incidences in the right and left stent frames. Proximal displacement was significantly more frequent among patients whose anatomy did not conform to any IFU (p=0.025). Presence of aneurysm growth ⩾5 mm was observed in 14 (19%) patients and was significantly associated with proximal displacement ⩾4 mm (p=0.03). Conclusion: Infrarenal EVAS may be complicated by proximal displacement and migration, particularly when performed outside the IFU. The definition of migration used for endovascular aneurysm repair may be inappropriate for EVAS; a new consensus on definition and measurement technique is necessary.

Complications and Reinterventions After Fenestrated and Branched EVAR in Patients with Paravisceral and Thoracoabdominal Aneurysms

The application of endovascular strategies to treat aneurysms involving the abdominal and thoracoabdominal aorta has evolved significantly since the inception of endovascular aneurysm repair. Advances in endograft technology and operator experience have enabled the management of a wider spectrum of challenging aortic anatomy. Fenestrated endovascular and branched endovascular aneurysm repair represent two technical innovations, which have expanded endovascular treatment options to include patients with paravisceral and thoracoabdominal aortic aneurysms. Although similar in many ways to standard aortic endografts, fenestrated and branched endografts have specific short- and long-term complications due to their unique modular endograft design and their sophisticated deployment mechanisms. This article aims to examine the commonly encountered complications with these devices and the endovascular reintervention strategies.

Fenestrated stent grafts for the treatment of complex aortic aneurysm disease: A mature treatment paradigm

The introduction of fenestrated stent grafts (SGs) to treat abdominal aortic aneurysms (AAAs) with short proximal necks began in 1999. Nowadays, the whole visceral aorta can be treated totally by endovascular means. The established use of fenestrated devices to treat complex AAAs as a first-line management option has been previously reported. An up-to-date evaluation of the literature was performed including all types of publications regarding the use of fenestrated technology to repair complex AAAs. Fenestrated repair is now an established alternative to hybrid/chimney/snorkel repairs. However, specific criteria and prerequisites are required for the use and improvement of this method. Multiple device morphologies have been used incorporating the visceral arteries in various combinations. This modular strategy connects different devices (bridging covered stents and bifurcated SGs) with the aortic main body, thus excluding the aneurysm from the circulation. Precise deployment of the fenestrated SG is mandatory for successful visceral vessel revascularization. Accurate SG sizing and customization, a high level of technical skill, and facilities with modern imaging techniques including 3D road mapping and dedicated hybrid rooms are required. Most experience has been with the custom-made Zenith Cook platform, although off-the-shelf devices have been recently implanted. More complex repairs have been performed over the last few years, but device complexity has also increased. Perioperative, mid-term, and a few recently reported long-term results are encouraging. Secondary interventions remain the main problem, similar to that observed after traditional endovascular abdominal aortic aneurysm repair (EVAR).

Systematic review and meta-analysis of migration after endovascular abdominal aortic aneurysm repair

Aim

To identify patients who are under higher threat for migration because of an old generation stent graft application.

Methods

A systematic review and meta-analysis of the literature was undertaken to identify all studies which included older generation endografts and data reporting on graft migration after EVAR. Outcome data were pooled and combined, and were calculated using fixed or random effects models.

Results

From 2000 to 2014, 22 retrospective studies were identified reporting on stent- graft migration after EVAR (8.6%). From those patients, 39% received re-intervention with the mean time of identification ranging from 12 to 36 months. Six of these retrospective nonrandomized studies were eligible for meta-analysis. AAA diameter (AAA diameter: 0.719 mm; 95% confidence interval [CI]: 0.00065–1.4384 mm; p = 0.00497) and neck length (neck length: 4.36 mm; 95% CI: 1.3277–7.394; p = 0.0048) were the only significant factors associated with stent- graft migration. Neck diameter and neck angulation did not have any important influence on stent-graft migration.

Conclusions

Patients with large AAA and short necks who were treated with older generation stent grafts such as AneurX and Talent are in higher risk for endograft migration than others. Stent- graft migration consists of an insidious and underestimated threat.