Endovascular Aneurysm Repair in Patients with Conical Neck Anatomy

The Challenge of Treating Abdominal Aortic Aneurysms with Hostile Neck Anatomy: An Overview

Hostile aortic neck anatomy challenges the outcomes of endovascular abdominal aortic aneurysm repair (EVAR). Besides reverting to open surgical repair (OSR), thoughtful endograft selection and a number of advanced endovascular techniques have been suggested as potential solutions for preventing proximal seal zone complications, improving EVAR durability, and preventing aneurysm-related death. Each technique is associated with advantages and limitations and there has not been a credible direct comparison amongst them in the form of a well-designed prospective trial. The not infrequent presence of multiple hostile anatomic characteristics further complicates decision making and challenges the surgeon's skills. This paper serves as an overview of hostile neck anatomy and its implications on EVAR. We provide a concise literature review with the purpose of outlining the treatment modalities and outcomes in this patient population.

Conical Aortic Neck as a Predictor of Outcome after Endovascular Aneurysm Exclusion: Midterm Results

BACKGROUND

Conical neck may affect endovascular aneurysm repair (EVAR) outcomes. The aim of this study was to present EVAR neck adverse events [endoleak type Ia (ET Ia) and graft migration], in patients with conical neck morphology compared to patients with non-conical necks. An additional analysis of the factors that may affect neck adverse events in patients with conical necks, during the first postoperative year, was executed.

METHODS

A retrospective analysis of prospective data was conducted, including patients that underwent elective EVAR, between 2017 and 2019. All patients completed the clinical and imaging follow-up of the initial 12 months. Regarding imaging, all cases underwent computed tomography angiography (CTA), preoperatively, at the 1st and 12th month of follow-up. Preoperative and postoperative aneurysm anatomic characteristics (supra-renal and infra-renal aortic diameters, aneurysm diameter, neck angle, thrombus, and calcification) were recorded. Proximal neck was defined as the infrarenal aortic segment, with a diameter less than 30 mm. Conical neck was any neck with a diameter increase ≥2 mm per cm of length (from outer-to-outer aortic wall). The proximal 15 mm of the neck length were considered the zone of endograft sealing. Migration was any ≥10 mm caudal movement of the endograft, relative to its position detected at the CTA of the first month. Neck adverse events were defined as the composite event of ET Ia and migration.

RESULTS

The cohort included 150 patients; 66 (44%) presented conical neck morphology. No significant difference was detected regarding the preoperative anatomic characteristics between the conical and non-conical groups. Only distal (15 mm) neck diameter was wider in the conical group (P < 0.001). Supra-renal active fixation was used in 63.3% of the total cohort; 59.5% in patients with non-conical necks and 68.2% in patients with conical morphology (P = 0.275). Graft oversizing was 18.2% and 18.7% in the non-conical and conical group, respectively (P = 0.248). Oversizing >20% was equal between groups [37.8% vs. 33.3%% (P = 0.608) while oversizing ≥30% was more common among patients with conical necks (3.5% vs. 10.6%, P < 0.001, 3.2 odds ratio, 95% confidence interval: 0.79, 12.91). Regarding ET Ia and migration, no difference was recorded between the groups. In a subanalysis among patients with conical necks, a lower graft migration rate was detected among patients with higher oversizing rate (P = 0.037).

CONCLUSIONS

EVAR may offer similarly good midterm outcomes in patients with conical and non-conical neck anatomy. An oversizing to the higher suggested rate may be preventive of graft migration during the first postoperative year in necks with conical morphology. Aggressive oversizing (>20%) do not offer any benefit regarding the prevention of adverse events among patients with conical necks.

Early Clinical Outcomes of the Active Seal Technology of the AFX Endovascular Aortic Aneurysm System With the VELA Cuff for Patients With a Conical Proximal Neck

PURPOSE

To evaluate the efficacy of the Active Seal technology employed in the AFX endovascular aortic aneurysm system (AFX), during endovascular aneurysm repair (EVAR) in patients with abdominal aortic aneurysms (AAAs) having a conical proximal neck.

MATERIALS AND METHODS

A retrospective analysis of the EVAR for AAA with a conical proximal neck using the AFX was performed at 17 Japanese hospitals between January 2016 and August 2020. The conical proximal neck was defined as a cone-shaped proximal neck, with more than 10% diameter increase within a 15 mm length at the proximal landing zone. All anatomical analyses were performed in the core laboratory, and cases with parallel walls within the proximal neck adequate for the landing zone were excluded from the study.

RESULTS

This study included 53 patients, but only 39 patients (mean age, 76.6 ± 6.7 years; 87.0% males; mean aneurysm diameter, 52.0 ± 8.0 mm) were analyzed after being characterized as having a pure conical neck by the core laboratory. The mean proximal neck diameters at the lower renal artery and proximal edge of the aneurysm were 20.0 ± 2.9 mm and 27.5 ± 4.9 mm, respectively. The mean proximal neck length was 21.5 ± 6.0 mm. Instructions for use violations other than the conical neck were observed in 15 patients (38.5%). The VELA cuff was used in all cases; however, additional proximal cuff was required in 9 more cases (23.1%). The Active Seal technology was able to significantly extend the proximal sealing zone from 21.5 ± 6.0 to 26.0 ± 12.2 mm (p = .047). Thirty-six patients completed the 12-month follow-up (one patient was lost to follow-up, and 2 patients died from causes unrelated to the aneurysm), and there were no type-1a and 3 endoleaks with only one reintervention (2.6%) related to type 1b endoleak in the 12-month period. Furthermore, there was no significant enlargement of the proximal neck diameter at 12 months (at 1 month: 20.6 ± 3.4 mm and at 12 months: 21.3 ± 3.8 mm; p = .420).

CONCLUSION

The Active Seal technology of the AFX significantly extended the proximal seal zone and no type-1a endoleak and proximal neck dilation was observed in patients with conical proximal neck at 12 months.

Endografts for the treatment of abdominal aortic aneurysms with a hostile neck anatomy: A systematic review

Background

Endovascular aortic repair (EVAR) of abdominal aortic aneurysms (AAAs) has emerged as a better alternative to conventional open surgery for AAAs. The purpose of the review is to define the improvement in the clinical management of the patient with hostile neck AAAs due to the introduction of new endografts while giving a thorough description of their instructions for use (IFUs), main characteristics and part sizing, reporting their outcomes from clinical studies and categorizing their usability.

Methods

A MEDLINE search was conducted using keyword-specific combinations. Clinical studies were searched via the clinicaltrials.gov website. Relevant articles' references were also hand-searched.

Results

We retrieved 640 records describing Alto, Ovation iX, Treovance, Aorfix, Anaconda, Conformable, and Endurant II/IIs endografts. Aortic necks >60° can be managed with Anaconda, Aorfix, and Conformable, which can treat up to 90° necks requiring ≥15 mm (Anaconda ≥20 mm), and Treovance, which is eligible for necks ≤75° with ≥15 mm length. Ovation's innovation of combining polymer-filled O-rings with integral anchors can treat conical necked AAAs giving Ovation iX and Alto an advantage. Short-necked AAAs can be treated with Alto, eligible for necks as short as 7 mm, and Endurant II, which can treat ≥10 mm necks or 4 mm if used in conjunction with the EndoAnchors system, respectively. Alto and Conformable report a 100% technical success rate, absence of AAA-related death, migration, ruptures, and limb occlusion during follow-up. Endurant II and Ovation iX report >99% technical success rate and are almost free from the AAA mortality rate, ruptures, migration, and limb occlusion, while Ovation iX has a high rate of sac dilation (15.5%) in a 5-year follow-up. Anaconda is slightly better than Aorfix and Treovance, which are related to the lowest technical success rates, 98.3%, 96.3%, and 96%, respectively. Aorfix has the highest AAA mortality rate, 4% in a 60 month follow-up.

Conclusion

Most new generation endografts described have comparable results. They broaden the eligibility of patients for EVAR due to their unique technical characteristics described. There is a lack of comparative studies for newer endografts and postmarket clinical studies with long-term results concerning the most recently approved devices described, Alto and Conformable.

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.

Long-term outcomes of endovascular aneurysm repair according to instructions for use adherence status

OBJECTIVE

Endovascular aneurysm repair (EVAR) has become a standard treatment method for abdominal aortic aneurysms (AAA). Endovascular device manufacturers have defined specific anatomic criteria for aneurysm characteristics to be observed as instructions for use (IFU) with specific grafts. In clinical practice, the prevalence of performing EVAR outside the IFU is high. This study aims to determine the impact of IFU criteria non-adherence on outcomes.

METHODS

Patients undergoing EVAR for an infrarenal AAA between 2005 and 2013 were included. IFU non-adherence was defined as any violation of device-specific IFU criteria and was compared to IFU adherence. Primary outcomes were all-cause mortality, aneurysm-related mortality, AAA ruptures, graft-related adverse events (GRAEs), including limb-related adverse events, and type Ia endoleaks. Secondarily, the aim was to study whether the prevalence of EVAR performed outside the IFU has increased over time.

RESULTS

A total of 258 patients were included, 144 (55.8%) of whom were treated according to the IFU criteria and 114 (44.2%) outside the criteria. In the IFU non-adherence group, all-cause mortality (HR 1.39, 95% CI 1.02-1.89, p = .037) and aneurysm-related mortality (HR 5.1, 95% CI 1.4-18.6, p = .015) were higher, as were the incidences of AAA ruptures (HR 5.4, 95 % CI 1.1-26.6, p = .036) and GRAEs (HR 1.7, 95% CI 1.1-2.8, p = .025). No significant association was found between type Ia endoleak and neck-related IFU or limb-related adverse events and iliac-related IFU. However, neck length was a risk factor for a type Ia endoleak (HR 18.2, 95% CI 6.3-52.2, p < .001), aneurysm-related mortality (HR=8.7, 95% CI 1.8-41.6, p = .007), rupture (HR= 21.7, 95% CI 2.8-166, p = .003), and GRAEs (HR 4.4, 95% CI 2.0-9.7, p < .001). An IFU violation regarding the neck angulation was also a risk factor for all-cause mortality (HR 2.0, 95% CI 1.1-3.7, p = .032), aneurysm-related mortality (HR 7.6, 95% CI 1.4-42.8, p = .021), AAA rupture (HR 79.4, 95% CI 6.3-999, p = .001), and GRAEs (HR 4.3, 95% CI 1.9-9.5, p < .001). The prevalence of EVAR performed outside the IFU did not increase over time.

CONCLUSIONS

Performing EVAR outside the IFU has a negative effect on outcomes, including all-cause mortality, aneurysm-related mortality, ruptures, and graft-related adverse events. Neck angulation and neck length seem to be the most crucial aneurysm characteristics.

Long-term outcomes of open and endovascular abdominal aortic repair in younger patients

OBJECTIVES

To evaluate long-term results in abdominal aortic aneurysm (AAA) surgery by either open (OAR) or endovascular (EVAR) repair in patients under 70 years of age.

METHODS

A retrospective analysis of a prospectively collected database of patients with age under 70 years old undergoing elective infrarenal AAA surgery between 2010 and 2018 was performed. The study population was divided into two groups: OAR and EVAR. The primary end-points were overall survival and aneurysm-related death, while secondary outcomes were need for reintervention and development of minor and major complications.

RESULTS

191 patients younger than 70 years old treated for elective AAA surgery were enrolled: 157 OAR (98% males, mean age 65 ± 4 years) and 34 EVAR (94% males, mean age 66 ± 4 years). Hospital stay, 30-day mortality and need for reintervention were similar; OAR population presented higher incidence of postoperative major complications (18% vs 2.9%; p .01) while minor complications were 32% in OAR vs 21% in EVAR group (p .08). Median follow-up was 69 months for OAR (IQR 53 months) vs. 79 months (IQR 51 months) for EVAR (p .9): long-term AAA-related reinterventions were more frequent after EVAR (1.9% OAR vs. 17% EVAR; p .01) while AAA-related long-term mortality was similar in both sugroups (1.3% OAR and 3% EVAR; p .8). At univariate analysis a higher risk of reintervention was reported for conical necks in EVAR group (p .03) and for the concomitant presence of iliac aneurysms in both groups (p .01).

CONCLUSIONS

In our population, the presence of a conical neck is an independent predictor of EVAR failure and late reintervention, while it does not play a significant role in OAR group. For this reason, in such cases, open surgery must be considered as the first option in younger patients with a long-life expectancy.

Open repair versus evar with parallel grafts in patients with juxtarenal abdominal aortic aneurysm excluded from fenestrated endografting

BACKGROUND

We compared the outcomes of open surgical repair (OSR) versus EVAR with parallel graft technique (PG) in patients with juxtarenal abdominal aortic aneurysm (JAAA) excluded from fenestrated endovascular aortic repair (FEVAR) due to clinical, anatomical, technical or manufacturing time reasons.

METHODS

A single-center analysis of consecutive patients who underwent elective and urgent (within 24-48 hours) repair of JAAA from January 2010 to January 2019 was performed. Two groups were compared: patients excluded from FEVAR and respectively treated by OSR or by PG for JAAA. Perioperative clinical, anatomic and operative data were collected in a dedicated database. The endpoints were primary technical success, changes in renal function, early and long-term mortality, freedom from aortic related reinterventions (ARRs) and aortic related mortality (ARM).

RESULTS

118 consecutive patients were treated for JAAA, 32 of them (27.1%) with FEVAR. 86 patients were enrolled in the study (OSR group=61; PG group= 25). The mean age was 77.4 ± 6.5 years for PG group and 71.1 ± 6.7 years for OSR group (p=.0001); the average comorbidity score of the Society for Vascular Surgery was higher for patients treated by PG (10.2 ± 4.8 vs 5.5 ± 0.4, p=.0001), with no differences for hypertension and renal score. After propensity score matching, 42 patients (OSR=27 ; PG=15) without differences in the preoperative risk factors were selected. Conical shape and neck mural thrombus were respectively more represented in the OSR group (95.1% vs 56.0%; 63.9% vs 36.0%). Aortic clamp site was supraceliac for 12 patients (19.7%), suprarenal for 21 (34.4%) and trans-renal for 28 patients (45.9%). In the PG group, 16 patients (64%) were treated with a single renal chimney. Primary technical success was similar in the two groups (100.0% vs 92.0%, p=.08), with an higher rate of procedure achieved by assisted technical success for the PG group after propensity score matching analysis (20.0% vs 0%, p=.04). Deterioration of renal function occurred for both groups of patients, with a significant creatinine increasing 12 months after surgery in the PG group compared with OSR group (1.72 ± 0.66 vs 1.18 ± 0.40, p=.006). Multiple logistic regression shows no independent predictor of peri-operative medical complication among demographics and pre-operative relevant clinical factors between the two cohorts. No difference in terms of early mortality was observed between the groups (1.6 % vs 0%, p=1.00). At 5 years, overall survival was lower for patients treated by PG (53.5% vs 70.2%, p=.007), such as freedom from ARRs (64.6 vs 90.5%, p=.03). Freedom from ARM at 5 years did not show significant differences among the two groups (100% vs 98.4%, p=1.00).

CONCLUSIONS

PG represents a feasible procedure for patients excluded from FEVAR due to clinical, anatomical, technical or device manufacturing time reasons, ensuring low rates of ARM. However, ARRs during the follow-up remain the Achilles heel of this technique. OSR is still the most durable procedure in the endovascular era, allowing the treatment of proximal "hostile necks" with low rates of reoperation and a similar impact on the renal function compared to PG.