Neck diameter and inner curve seal zone predict endograft-related complications in highly angulated necks after endovascular aneurysm repair using the Aorfix endograft

Hostile Neck Index is a Novel and Strong Predictor of Type I Endoleak Development After Endovascular Aortic Repair for Abdominal Aortic Aneurysm

BACKGROUND

This study aimed to investigate the predictive value in the development of type I endoleak in patients undergoing elective endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA).

METHODS

Clinical and radiological imaging data of 105 patients who underwent EVAR procedure due to AAA between August 2019 and May 2024 were evaluated. The patients were divided into 2 groups according to whether or not periprocedural type I endoleak developed; as the nonendoleak group (n = 82) and endoleak group (n = 23). The patients' preprocedural demographic and clinical characteristics as well as periprocedural data were compared between the groups. After univariate analyses, multivariate logistic regression analysis was performed to determine independent predictors of endoleak development of perioperative mortality and receiver operating characteristic curve analysis was performed to determine the cut-off values of the identified endoleak predictors.

RESULTS

When the preprocedural baseline demographic and clinical characteristics of the groups were compared; the mean ages in the nonendoleak group and endoleak group were found to be 73.0 ± 8.9 and 72.0 ± 6.9 years, respectively. The mean values of aortic neck diameter, aortic neck angulation, and hostile neck index (HNI) were found to be significantly higher, while the mean value of aortic neck length was found to be significantly lower in endoleak group compared to nonendoleak group. In logistic regression analysis, only HNI was found to be an independent predictor of type I endoleak. To predict endoleak development, an optimal cut-off value of 60.95 was determined for HNI with 95.7% sensitivity and 61.0% specificity in receiver operating characteristic curve analysis (area under the curve = 0.755, 95% confidence interval = 0.657-0.852).

CONCLUSIONS

This study revealed, for the first time in the literature, that high HNI levels significantly and independently predicted the development of periprocedural type I endoleak in patients undergoing EVAR procedure for AAA.

Geometric Analysis of the Gore Excluder Conformable Endoprosthesis in the Infrarenal Aortic Neck: One Year Results of the EXCeL Registry

OBJECTIVE

The Gore Excluder Conformable Endoprosthesis (CEXC) is designed to treat challenging infrarenal anatomy because of its active angulation control, repositionability, and enhanced conformability. This study evaluated 30 day and one year position and apposition of the CEXC in the infrarenal neck.

METHODS

Patients treated with the CEXC between 2018 and 2022 with an available 30 day computed tomography angiogram (CTA) were selected from four hospitals in a prospective registry. Endograft apposition (shortest apposition length [SAL]) and position (shortest fabric distance [SFD]) were assessed on the 30 day and one year CTAs. Maximum infrarenal aortic curvature was compared between the pre- and post-operative CTAs to evaluate conformability of the CEXC.

RESULTS

There were 87 patients with a 30 day CTA, and for 56 of these patients the one year CTA was available. Median (interquartile range [IQR]) pre-operative neck length was 22 mm (IQR 15, 32) and infrarenal angulation was 52° (IQR 31, 72). Median SAL was 21.2 mm (IQR 14.0, 29.3) at 30 days for all included patients. The SAL in 13 patients (15%) was < 10 mm at 30 days, and one patient had a SAL of 0 mm and a type Ia endoleak. There was no significant difference in SAL between patients within and outside instructions for use. The SAL significantly increased by 1.1 mm (IQR -2.3, 4.7; p = .042) at one year. The SAL decreased in seven patients (13%), increased in 13 patients (23%), and remained stable in 36 patients (64%). Median SFD was 2.0 mm (IQR 0.5, 3.6) at 30 days, which slightly increased by 0.3 mm (IQR -0.5, 1.8; p = .019) at one year. One patient showed migration (SFD increase ≥ 5 mm). Median endograft tilt was 15.8° (IQR 9.7, 21.4). Pre-operative maximum infrarenal curvature was 36 m-1 (IQR 26, 56) and did not significantly change thereafter.

CONCLUSION

In most patients, the CEXC was implanted close to the renal arteries, and sufficient (≥ 10 mm) post-operative apposition was achieved at 30 days, which slightly increased at one year. Post-operative endograft tilt was relatively low, and aortic geometry remained unchanged after implantation of the CEXC, probably due to its high conformability.

Risk factors of type 1A endoleak following endovascular aortic aneurysm repair

OBJECTIVES

Endovascular repair of infrarenal aortic aneurysms are the treatment of first choice. However, the proximal sealing of endovascular aneurysm repair is the Achilles' heel of the procedure. Insufficient proximal sealing can lead to endoleak type 1A and therefore expansion of the aneurysm sack and subsequent rupture.

METHODS

We performed a retrospective analysis of all consecutive patients with an infrarenal abdominal aneurysm treated with endovascular aneurysm repair. We studied whether demographic and anatomical features were risk factors for endoleak type 1A. Also, the results of different treatment strategies were described.

RESULTS

257 Patients were included in the study, most patients were male. In the multivariate analysis, female gender and infrarenal angulation were the most important risk factors for endoleak type 1A. Endoleak type 1A diagnosed at completion angiography disappeared in 77.8%. The occurrence of endoleak type 1A was associated with a higher risk of aneurysm-related mortality (p = 0.01).

CONCLUSION

Conclusions should be drawn with care, since the number of patients included in this study was small and there was a high incidence of patients lost to follow-up. This study suggests that endovascular aneurysm repair in female patients and patients with severe infrarenal angulation is associated with a higher risk of endoleak type 1A.

Insight from an Italian Delphi Consensus on EVAR feasibility outside the instruction for use: the SAFE EVAR Study

BACKGROUND

The SAfety and FEasibility of standard EVAR outside the instruction for use (SAFE-EVAR) Study was designed to define the attitude of Italian vascular surgeons towards the use of standard endovascular repair (EVAR) for infrarenal abdominal aortic aneurysm (AAA) outside the instruction for use (IFU) through a Delphi consensus endorsed by the Italian Society of Vascular and Endovascular Surgery (Società Italiana di Chirurgia Vascolare ed Endovascolare - SICVE).

METHODS

A questionnaire consisting of 26 statements was developed, validated by an 18-member Advisory Board, and then sent to 600 Italian vascular surgeons. The Delphi process was structured in three subsequent rounds which took place between April and June 2023. In the first two rounds, respondents could indicate one of the following five degrees of agreement: 1) strongly agree; 2) partially agree; 3) neither agree nor disagree; 4) partially disagree; 5) strongly disagree; while in the third round only three different choices were proposed: 1) agree; 2) neither agree nor disagree; 3) disagree. We considered the consensus reached when ≥70% of respondents agreed on one of the options. After the conclusion of each round, a report describing the percentage distribution of the answers was sent to all the participants.

RESULTS

Two-hundred-forty-four (40.6%) Italian Vascular Surgeons agreed to participate the first round of the Delphi Consensus; the second and the third rounds of the Delphi collected 230 responders (94.3% of the first-round responders). Four statements (15.4%) reached a consensus in the first rounds. Among the 22 remaining statements, one more consensus (3.8%) was achieved in the second round. Finally, seven more statements (26.9%) reached a consensus in the simplified last round. Globally, a consensus was reached for almost half of the proposed statements (46.1%).

CONCLUSIONS

The relatively low consensus rate obtained in this Delphi seems to confirm the discrepancy between Guideline recommendations and daily clinical practice. The data collected could represent the source for a possible guidelines' revision and the proposal of specific Good Practice Points in all those aspects with only little evidence available.

How to combine CTA, 99mTc-WBC SPECT/CT, and [18F]FDG PET/CT in patients with suspected abdominal vascular endograft infections?

PURPOSE

We aimed at comparing 99mTc-HMPAO white blood cells (99mTc-WBC) scintigraphy, 18fluorine-fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) and CT angiography (CTA) in patients with suspected abdominal vascular graft or endograft infection (VGEI). Moreover, we attempted to define a new visual score for interpreting [18F]FDG PET/CT scans aiming at increasing its specificity.

METHODS

We prospectively compared 99mTc-WBC SPECT/CT, [18F]FDG PET/CT, and CTA in 26 patients with suspected abdominal VGEI. WBC scans were performed and interpreted according to EANM recommendations. [18F]FDG PET/CT studies were assessed with both qualitative (Sah's scale and new visual score) and semi-quantitative analyses. CTA images were interpreted according to MAGIC criteria. Microbiology, histopathology or a clinical follow-up of at least 24 months were used to achieve final diagnosis.

RESULTS

Eleven out of 26 patients were infected. [18F]FDG PET/CT showed 100% sensitivity and NPV, with both scoring systems, thus representing an efficient tool to rule out the infection. The use of a more detailed scoring system provided statistically higher specificity compared to the previous Sah's scale (p = 0.049). 99mTc-WBC SPECT/CT provided statistically higher specificity and PPV than [18F]FDG PET/CT, regardless the interpretation criteria used and it can be, therefore, used in early post-surgical phases or to confirm or rule out a PET/CT finding.

CONCLUSIONS

After CTA, patients with suspected late VGEI should perform a [18F]FDG PET/CT given its high sensitivity and NPV. However, given its lower specificity, positive results should be confirmed with 99mTc-WBC scintigraphy. The use of a more detailed scoring system reduces the number of 99mTc-WBC scans needed after [18F]FDG PET/CT. Nevertheless, in suspected infections within 4 months from surgery, 99mTc-WBC SPECT/CT should be performed as second exam, due to its high accuracy in differentiating sterile inflammation from infection.

Aligning Orifice of the Renal Artery with Fish-Mouth FIXation Technique During Endovascular Aortic Aneurysm Repair for Hostile Neck Anatomy

Background: As the success of endovascular aortic aneurysm repair (EVAR) depends on sufficient proximal fixation of the endograft to the aortic wall, the proximal hostile neck anatomy (HNA) is the major potential treatment-limiting factor in EVAR. The Aorfix endovascular stent graft was designed to operate on highly angulated aortic necks. The Aligning Orifice of the Renal artery with fish-mouth FIXation (AORFIX) technique uniquely and accurately aligns the trough part of the proximal stent end with the orifice of the lower renal artery and is used to optimize the proximal fish-mouth design for maximum proximal seal use. Herein, we aimed to evaluate the usefulness of the AORFIX technique for EVAR in patients with HNA. Methods: Eighty-one consecutive patients who underwent EVAR with the AORFIX technique (+AORFIX technique group, n = 16) and without (standard group, n = 65) were evaluated. The HNA was defined as any of the following: neck angulation ≥60°, neck length ≤15 mm, or neck thrombus or calcification ≥50% of the circumference and conical neck. Results: Each HNA criterion was similar between the two groups. However, the average number of HNA criteria was significantly higher in the +AORFIX technique group (1.9 ± .2 vs. 1.3 ± .1; P < .01). The two groups showed 100% procedural success. The concurrent renal angioplasty and stenting rates (88% vs. 4.6%; P < .01) were significantly higher in the +AORFIX technique group. There were no 30-day deaths in either group and no in-hospital device-related events in the +AORFIX technique group. The median follow-up period was 39 months, and there was no significant between-group difference in freedom from reintervention rate (+AORFIX group vs. standard group, 100% vs. 91.0%; P = .327). Conclusion: EVAR using the AORFIX technique might be useful even in patients with more complex HNA.

Pre-operative Aortic Neck Characteristics and Post-operative Sealing Zone as Predictors of Type 1a Endoleak and Migration After Endovascular Aneurysm Repair: A Systematic Review and Meta-Analysis

OBJECTIVE

Establishing the predictive value of neck characteristics and real achieved sealing zone is essential to foster risk stratified procedure selection and imaging surveillance. This systematic review provides an overview of pre-operative aortic neck characteristics and post-operative real achieved sealing zone and their respective risk of type 1a endoleak and migration after endovascular aneurysm repair (EVAR).

METHODS

In agreement with PRISMA guidelines, MEDLINE, Embase, and Cochrane CENTRAL were searched. Data on neck characteristics, sealing zone, and EVAR outcome were extracted. Meta-analyses were performed to investigate the effect of neck diameter, angulation, and shape on type 1a endoleak (total, early ≤ 90 days, and late > 90 days) and migration in patients who underwent EVAR. A qualitative summary was also provided.

RESULTS

Thirty-three studies were included. Patients with a larger neck diameter had an increased risk of total type 1a endoleak (nine studies: OR 3.32, 95% CI 2.38 - 4.63), early type 1a endoleak (six studies: OR 2.64, 95% CI 1.27 - 5.48), late type 1a endoleak (six studies: OR 3.26, 95% CI 2.12 - 5.03), and migration (seven studies: OR 2.88, 95% CI 1.32 - 6.26). An angulated neck increased the risk of total type 1a endoleak (seven studies: OR 4.27, 95% CI 1.55 - 11.78) and late type 1a endoleak (seven studies: OR 5.56, 95% CI 2.19 - 14.13). Neck shape was not associated with type 1a endoleak. Neck length and real achieved sealing zone on post-EVAR computed tomography were identified as risk factors for type 1a endoleak and migration through qualitative summary.

CONCLUSION

There seems to be some consistent evidence that aortic neck diameter, angulation, and length are associated with the development of type 1a endoleak or migration. Real achieved sealing zone might be an important addition during follow up. However, a small number of studies, with serious limitations, could be included, and there was considerable variability in reporting patients and outcomes. A proposal for standardisation of aortic and EVAR data in future studies is provided.

Fast and Accurate Computation of the Displacement Force of Stent Grafts after Endovascular Aneurysm Repair

Purpose: Currently, the displacement force of stent grafts is generally obtained using computational fluid dynamics (CFD), which requires professional CFD knowledge to perform the correct simulation. This study proposes a fast, simple, and clinician-friendly approach to calculating the patient-specific displacement force after endovascular aneurysm repair (EVAR). Methods: Twenty patient-specific post-EVAR computed tomography angiography images were used to reconstruct the patient-specific three-dimensional models, then the displacement forces were calculated using CFD and the proposed approaches, respectively, and their numerical differences were compared and analyzed. Results: Based on the derivation and simplification of the momentum theorem, the patient-specific displacement forces were obtained using the information of the patient-specific pressure, cross-sectional area, and angulation of the two stent graft ends, and the average relative error was no greater than 1.37% when compared to the displacement forces calculated by CFD. In addition, the linear regression analysis also showed good agreement between the displacement force values calculated by the new approach and CFD (R = 0.999). Conclusions: The proposed approach can quickly and accurately calculate the patient-specific displacement force on a stent graft and can therefore help clinicians quickly evaluate the post-EVAR displacement force.

Is Evar Feasible in Challenging Aortic Neck Anatomies? A Technical Review and Ethical Discussion

Background: Endovascular aneurysm repair (EVAR) has become an accepted alternative to open repair (OR) for the treatment of abdominal aortic aneurysm (AAA) despite “hostile” anatomies that may reduce its effectiveness. Guidelines suggest refraining from EVAR in such circumstances, but in clinical practice, up to 44% of EVAR procedures are performed using stent grafts outside their instruction for use (IFU), with acceptable outcomes. Starting from this “inconsistency” between clinical practice and guidelines, the aim of this contribution is to report the technical results of the use of EVAR in challenging anatomies as well as the ethical aspects to identify the criteria by which the “best interest” of the patient can be set. Materials and Methods: A literature review on currently available evidence on standard EVAR using commercially available endografts in patients with hostile aortic neck anatomies was conducted. Medline using the PubMed interface and The Cochrane Library databases were searched from 1 January 2000 to 6 May 2021, considering the following outcomes: technical success; need for additional procedures; conversion to OR; reintervention; migration; the presence of type I endoleaks; AAA-related mortality rate. Results: A total of 52 publications were selected by the investigators for a detailed review. All studies were either prospective or retrospective observational studies reporting the immediate, 30-day, and/or follow-up outcomes of standard EVAR procedures in patients with challenging neck anatomies. No randomized trials were identified. Fourteen different endo-grafts systems were used in the selected studies. A total of 45 studies reported a technical success rate ranging from 93 to 100%, and 42 the need for additional procedures (mean value of 9.04%). Results at 30 days: the incidence rate of type Ia endoleak was reported by 37 studies with a mean value of 2.65%; 31 studies reported a null migration rate and 32 a null conversion rate to OR; in 31 of the 35 studies that reported AAA-related mortality, the incidence was null. Mid-term follow-up: the incidence rate of type Ia endoleak was reported by 48 studies with a mean value of 6.65%; 30 studies reported a null migration rate, 33 a null conversion rate to OR, and 28 of the 45 studies reported that the AAA-related mortality incidence was null. Conclusions: Based on the present analysis, EVAR appears to be a safe and effective procedure—and therefore recommendable—even in the presence of hostile anatomies, in patients deemed unfit for OR. However, in order to identify and pursue the patient’s best interest, particular attention must be paid to the management of the patient’s informed consent process, which—in addition to being an essential ethical-legal requirement to legitimize the medical act—ensures that clinical data can be integrated with the patient’s personal preferences and background, beyond the therapeutic potential of the proposed procedures and what is generically stated in the guidelines.

Use of Chimney Technique Does Not Improve the Outcome of Endovascular Aneurysm Repair in Patients With a Hyperangulated and Short Proximal Aortic Neck

PURPOSE

We hypothesized that extending the proximal landing zone with the chimney technique could be beneficial in patients with a hyperangulated proximal aortic neck, defined as more > 60 degrees.

MATERIAL AND METHODS

We retrospectively analyzed the outcome of prospectively collected data of patients treated by endovascular aneurysm repair (EVAR) for infrarenal aortic aneurysm with a hyperangulated proximal aortic neck. In all, 104 out of 130 patients were treated without (Group A) and 24 with the chimney endovascular aortic repair (ChEVAR, Group B). Primary outcome was technical and clinical success according to the reporting standards of the Society of Vascular Surgery.

RESULTS

The use of the chimney technique was associated with a significantly longer operation duration (167 vs. 93 min, p < .001), longer fluoroscopy time (44 vs.30 min, p = < .001), and larger amount of contrast medium used (149 vs. 127 ml, p = .03) but did not significantly improve technical (79.2% vs. 87.7%) and clinical success (54.2% vs. 68.9%). Aneurysm-related mortality was higher in group B (8.3% vs. = 0%, p < .001). Type IA endoleak was high in both groups at completion angiography (11.3% in Group A vs. 12.5% in Group B) and at follow-up (10.4% in Group A vs. 4.5% in Group B) without significant difference between the groups.

CONCLUSIONS

Our data did not show a benefit of the primary use of the chimney technique in patients with a hyperangulated and short neck, although more studies are required to support this conclusion. Other strategies or new technologies are required for improving EVAR results in aneurysm patients with severe angulated proximal and short neck.

Excluder Stent Graft-Related Outcomes in Patients with Aortic Neck Anatomy Outside of Instructions For Use (IFU) within the Global Registry for Endovascular Aortic Treatment (GREAT): Mid-term Follow-Up Results

BACKGROUND

The utilisation rate of endovascular aortic aneurysm repair has increased continuously over the past 2 decades. Endovascular aortic aneurysm repair is still performed frequently in patients with an unfavourable proximal seal zone, despite the associated late complications.

PURPOSE

We aimed to evaluate the mid-term durability of the GORE® EXCLUDER® AAA Endoprosthesis, featuring the C3 delivery system, in patients with a proximal neck anatomy outside the instructions for use (IFU).

METHODS

A retrospective sub-analysis of the Global Registry for Endovascular Aortic Treatment including patients treated for abdominal aortic aneurysms with the GORE EXCLUDER AAA Endoprosthesis (W.L. Gore & Associates, Inc, Flagstaff, Arizona) was performed. A "challenging neck" was defined as those treated outside the IFU with an aortic neck length <15 mm and/or aortic neck angle >60°. Cox proportional analyses were used to test for time-to-event differences between those treated within and outside the IFU while accounting for covariates, specifically proximal neck length and neck angle. The main outcomes assessed were 5-year all-cause mortality, 5-year endoleak development (type I or III), and 5-year device-related reinterventions.

FINDINGS

Of the 3,324 patients included in the analysis, 411 (12.4%) had a challenging neck and 2,913 (87.6%) did not. The patients in the challenging neck group were significantly older (74.9 years vs. 73.2 years, p≤0.0001) and had a significantly larger aortic aneurysm diameter at the time of the intervention than those treated within the IFU (61.2 mm vs. 56.4 mm, P< 0.0001), shorter proximal neck length (18 mm vs. 30 mm, P< 0.0001) and larger infrarenal neck angle (60.8° vs. 25.8°, P< 0.0001). In the multivariate analysis, brachial access site and challenging neck were not independent risk factors; increased age was associated with a shorter time to mortality (hazard ratio 1.051, 95% confidence interval 1.039-1.062, P< 0.0001), as was the use of tobacco (hazard ratio 1.329, 95% confidence interval 1.124-1.571, P= 0.0009). The 5-year all-cause mortality (36.2% vs. 27.5%, P= 0.002) and aorta-related mortality (3.8% vs. 1.1%, P= 0.002) were significantly higher in the challenging neck group. The risk of death within 5 years also increased significantly at 1.1% per millimetre increase in the abdominal aortic aneurysm diameter (P= 0.0005). Furthermore, the rates of type Ia endoleak development (7% vs. 1.2%, P< 0.001) and requirement for reintervention (13.3% vs. 9.7%, P< 0.001) were higher in those treated outside the IFU (challenging neck group).

CONCLUSIONS

Treatment with the Excluder AAA Endograft outside the IFU was associated with higher 5-year mortality values, increased type Ia endoleak development rates, and a greater need for reintervention compared with treatment within the IFU. This reiterates that fenestrated and open treatments should be strongly considered in cases with aortic neck anatomies outside the IFU. Infrarenal endovascular intervention outside the IFU should only be used when there is no alternative, with meticulous procedural planning and intervention to promote satisfactory outcomes.

Current assessment and management of endoleaks after advanced EVAR: new devices, new endoleaks?

INTRODUCTION

In recent years there has been an increasing application of advanced EVAR techniques to tackle complex clinical and anatomical scenarios. In a bid to overcome the limitations of the traditional stent-grafts, newer EVAR endografts and techniques have been developed and introduced into clinical practice, permitting endovascular management of difficult infrarenal, juxta-renal and thoracoabdominal aneurysms for which previously there was no endovascular solution. As a consequence, we are now confronted with unique patterns of endoleak requiring customized clinical-radiological assessment and treatment. Despite the increasing body of evidence regarding new EVAR techniques and related endoleaks, current guidelines do not specifically address these issues.

OBJECTIVES

Our review aims to assess risk factors, development, and management strategies of these endoleaks, in the most recent infrarenal EVAR devices and in more complex fenestrated EVAR (FEVAR) and Chimney EVAR (Ch-EVAR).

EXPERT OPINION

Most new devices have demonstrated types of endoleaks that need specific imaging and treatment, as in EVAS, FEVAR, and ChEVAR. Knowledge of specific stent-graft characteristics and the nature of endoleaks associated with the various procedures facilitates the application of relevant useful imaging. In addition, it should aid development of a customized and practically relevant approach to patient management during intervention and follow-up.