Comparison of aortic neck dilatation after open and endovascular repair of abdominal aortic aneurysm

Midterm outcomes of "wide neck" abdominal aortic aneurysm after open or endovascular repair in two European centers: a propensity score matching analysis

BACKGROUND

The aim of this study was to compare mid-term clinical and morphological outcomes in patients undergoing open (OR) and endovascular aortic repair (EVAR) with a proximal wide neck abdominal aortic aneurysm (WN-AAA).

METHODS

Between 2009 and 2014 data of all patients undergoing OR at IRCCS San Raffaele Hospital and EVAR at German Aortic Center Hamburg were retrospectively analyzed. Primary endpoints were aneurysm-related mortality at 5 years, reintervention, and overall mortality. Secondary endpoint was proximal neck enlargement. A 1:1 propensity score matching (PSM) was performed. Survival and freedom from AAA-related reintervention were investigated in matched OR and EVAR group by Kaplan-Meier analysis.

RESULTS

Of all OR performed at IRCCS San Raffaele Hospital 70 were found to have a proximal neck >28 mm (mean age: 69.8±7.2 years, 67 [95.71%] male); of all consecutive EVAR performed at German Aortic Center Hamburg, 52 required an endograft size of at least 32 mm (mean age of 73.1±8.7 years, 49 [94.2%] male). After PSM, the study cohort consisted of 30 OR and EVAR. One early mortality was registered in both groups (P=NS). Mid-term freedom from reintervention compared in OR and EVAR, with no statistically significant differences (P=0.979). Eight (15.4%) patients treated with EVAR developed a significant proximal diameter enlargement (≥3 mm) while only 1 (1.4%) patient in the OR group had the same evolution (P<0.01).

CONCLUSIONS

In WN-AAA neck enlargement is observed more frequently in patients undergoing EVAR, but reintervention rate was similar in the 2 groups, demonstrating that both options were safe and effective.

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.

A Scoping Review on the Incidence, Risk Factors, and Outcomes of Proximal Neck Dilatation after Standard and Complex Endovascular Repair for Abdominal Aortic Aneurysms

Background: To define proximal neck dilation (PND) after standard endovascular aneurysm repair (EVAR) and fenestrated EVAR (FEVAR), determining: incidence and risk factors; evidence base that links PND to outcomes of patients; recurring themes or gaps in the literature. Methods: We performed a scoping review and included only full-text English articles with follow-up focusing on PND in patients undergoing EVAR or FEVAR, published between 2000 and 2022. The following PICO question was used to build the search equation: in patients with abdominal-aortic-aneurysm (AAA) (Population) undergoing endovascular repair (Intervention), what are the incidence, risk factors and prognosis of radiologically defined PND (Comparison) on short-term and long-term outcomes (Outcomes)? Results: 15 articles were included after review. Measurement protocols for proximal aortic neck (PAN) varied among individual studies and the definition of PND resulted as heterogeneous. Rate of patients with a PND ranged between 0% and 41%. Large proximal neck (>28 mm) and excessive graft sizing (30%) were predictors for PND. New endografts with low outward radial forces and FEVAR seemed to be protective. Surgical conversion was the definitive option in the case of patients unfit for other endovascular treatments. Conclusions: PND is a frequent finding after EVAR and FEVAR. Excessive graft oversizing and large baseline PAN were predictors of neck enlargement, independently by the type of standard endograft used. FEVAR may be considered protective against complications, together with endografts using low outward radial forces. Lifelong radiological follow-up is mandatory.

A systematic review and meta-analysis of proximal aortic neck dilatation after endovascular abdominal aortic aneurysm repair

OBJECTIVE

To provide an updated systematic literature review summarizing current evidence on aortic neck dilatation (AND) after endovascular aortic aneurysm repair (EVAR) in patients with infrarenal abdominal aortic aneurysm.

METHODS

An extensive electronic search in major electronic databases was conducted between January 2000 and December 2021. Eligible for inclusion were observational studies that followed up with patients (n ≥ 20) undergoing EVAR with self-expanding endografts, for 12 or more months, evaluated AND with computed tomography angiography and provided data on relevant outcomes. The primary end point was the incidence of AND after EVAR, and the secondary end points were the occurrence of type Ia endoleak, stent graft migration, secondary rupture, and reintervention.

RESULTS

We included 34 studies with a total sample of 12,038 patients (10,413 men; median age, 71 years). AND was defined clearly in 18 studies, but significant differences in AND definition were evidenced. The pooled incidence of AND based on quantitative analysis of 16 studies with a total of 9201 patients (7961 men; median age, 72 years) was calculated at 22.9% (95% confidence interval [CI], 14.4-34.4) over a follow-up period ranging from 12 months to 14 years. The risk of a type Ia endoleak was significantly higher in AND patients compared with those without AND (odds ratio, 2.95; 95% CI, 1.10-7.93; P = .030). Similarly, endograft migration was more common in the AND group compared with the non-AND group (odds ratio, 5.95; 95% CI, 1.80-19.69; P = .004). The combined incidence of secondary rupture and reintervention did not differ significantly between the two groups, even though the combined effect was in favor of the non-AND group.

CONCLUSIONS

Proximal AND after EVAR is common and occurs in a large proportion of patients with infrarenal abdominal aortic aneurysm. AND can influence the long-term durability of proximal endograft fixation and is significantly related to adverse outcomes, often leading to reinterventions.

Abdominal aortic aneurysm neck dilatation and sac remodeling in fenestrated compared to standard endovascular aortic repair

OBJECTIVE

Contemporary commercially available endovascular devices for the treatment of abdominal aortic aneurysm (AAA) include standard endovascular aortic repair (sEVAR) or fenestrated EVAR (fEVAR) endografts. However, aortic neck dilatation (AND) can occur in nearly 25% of patients following EVAR, resulting in loss of proximal seal with risk of aortic rupture. AND has not been well characterized in fEVAR, and direct comparisons studying AND between fEVAR and sEVAR have not been performed. This study aims to analyze AND in the infrarenal and suprarenal aortic segments, including seal zone, and quantify sac regression following fEVAR implantation compared to sEVAR.

METHOD

A retrospective review of prospectively collected data on 20 consecutive fEVAR patients (Cook Zenith® Fenestrated) and 20 sEVAR (Cook Zenith®) patients was performed. Demographic data, anatomic characteristics, procedural details, and clinical outcome were analyzed. Pre-operative, post-operative (1 month), and longest follow-up CT scan at an average of 29.3 months for fEVAR and 29.8 months for sEVAR were analyzed using a dedicated 3D workstation (iNtuition, TeraRecon Inc, Foster City, California). Abdominal aortic aneurysm neck diameter was measured in 5 mm increments, ranging from 20 mm above to 20 mm below the lowest renal artery. Sub-analysis comparing the fEVAR to the sEVAR group at 12 months and at greater than 30 months was performed. Standard statistical analysis was done.

RESULTS

Demographic characteristics did not differ significantly between the two cohorts. The fEVAR group had a larger mean aortic diameter at the lowest renal artery, shorter infrarenal aortic neck length, increased prevalence of nonparallel neck shape, and longer AAA length. On follow-up imaging, the suprarenal aortic segment dilated significantly more at all locations in the fEVAR cohort, whereas the infrarenal aortic neck segment dilated significantly less compared to the sEVAR group. Compared to the sEVAR cohort, the fEVAR patients demonstrated significantly greater positive sac remodeling as evident by more sac diameter regression, and elongation of distance measured from the celiac axis to the most cephalad margin of the sac. Device migration, endoleak occurrence, re-intervention rate, and mortalities were similar in both groups.

CONCLUSION

Compared to sEVAR, patients undergoing fEVAR had greater extent of suprarenal AND, consistent with a more diseased native proximal aorta. However, the infrarenal neck, which is shorter and also more diseased in fEVAR patients, appears more stable in the post-operative period as compared to sEVAR. Moreover, the fEVAR cohort had significantly greater sac shrinkage and improved aortic remodeling. The suprarenal seal zone in fEVAR may result in a previously undescribed increased level of protection against infrarenal neck dilatation. We hypothesize that the resultant decreased endotension conferred by better seal zone may be responsible for a more dramatic sac shrinkage in fEVAR.

Risk factors and adverse events related to supra- and infra-renal aortic dilation at twelve months after endovascular abdominal aortic aneurysm repair

BACKGROUND

Aortic remodeling and its effect on adverse events after endovascular abdominal aneurysm repair (EVAR) remain under investigation. This study aimed to assess aortic diameter alterations after EVAR, related risk factors and consequences to proximal sealing at 12 months.

METHODS

A single-center retrospective analysis of consecutive EVAR patients was undertaken. All patients underwent computed tomography angiography, preoperatively, at 1^st and 12^th month. The infrarenal diameter was measured just below the inferior renal artery, at 7 mm and 15 mm while the suprarenal, just above the superior renal artery (SRA), superior mesenteric artery (SMA) and just below the celiac trunk. Neck-related adverse events included migration and endoleak Ia.

RESULTS

A hundred fifty patients were included. At 1^st month, no significant diameter alteration was recorded at any level. At 12^th month, all infra-renal diameters increased (P<0.001) and diameters at SRA and SMA also augmented (P=0.024 and P=0.007, respectively). Neck diameter >29 mm, supra-renal fixation and oversizing >20% were associated to dilation at 12^th month. Neck adverse events were related to diameter alterations below the inferior renal artery (P=0.017), SRA (P=0.007) and SMA (P=0.05).

CONCLUSIONS

During the 12-month follow-up, aortic dilation may be detected from the supra-renal aorta to the total neck length. Neck dilation may be attributed to large neck diameter, supra-renal fixation, and aggressive oversizing. Neck-related adverse events are more common in patients with aortic dilation at 12 months.

Identifying high risk for proximal endograft failure after EVAR in patients suitable for both open and endovascular elective aneurysm repair

INTRODUCTION

Proximal endograft failure (type Ia endoleak or migration) after endovascular aneurysm repair (EVAR) is associated with hostile aneurysm neck morphology. Neck scoring systems were developed to predict proximal endograft failure but were studied in retrospective studies, which due to selection bias may have led to an overestimation of bad outcomes after EVAR. To predict patients who benefit from open repair, preoperative neck morphology and occurrence of long-term proximal endograft failure were investigated in patients enrolled in the endovascular arm of the DREAM-trial who were suitable for open repair by definition and have long-term follow-up.

METHODS

A post-hoc on-treatment analysis of patients after EVAR was performed in 171 patients. Aneurysm neck morphology was quantified using the aneurysm severity grading (ASG)-neck score calculated on pre-operative CT-angiography images. The ASG-neck score was used to predict proximal endograft failure. ROC analysis was performed to calculate a threshold to divide favorable and unfavorable aneurysm necks (low and high-risk), positive and negative likelihood-ratios were calculated accordingly. Freedom from proximal endograft failure was compared between groups using Kaplan Meier analysis.

RESULTS

During a median follow-up of 7.6 years, 20 patients suffered proximal endograft failure. ROC analysis showed an AUC 0.77 (95% CI 0.65-0.90; p<0.001) indicating acceptable prediction. The threshold was determined at ASG-neck score ≥5, 30 patients had unfavorable neck morphology of whom 11 developed proximal endograft failure. The positive likelihood-ratio was 4.4 (95% CI 2.5-7.8) and the negative likelihood-ratio was 0.51 (95% CI 0.3-0.8). Twelve years postoperatively, freedom from proximal endograft failure was 91.7% in favorable and 53.2% in unfavorable groups, difference 38.5% (95% CI 13.9-63.1; p<0.001).

CONCLUSION

In this study, the ASG-neck score predicted proximal endograft failure during the entire follow-up. This exhibits the persistent risk for proximal endograft failure long after EVAR and calls for ongoing surveillance especially in patients with unfavorable aneurysm necks.

The retroperitoneal approach for contemporary open abdominal aortic aneurysm surgery: The anatomical reasoning

In current practice, the place of open surgery in managing abdominal aortic aneurysm is a contentious issue. The principal reason being greater applications of endovascular techniques treating increasingly complicated aortic disease. Development of branched and fenestrated devices enabled this, with numbers increasing annually. This meant a good risk patient with a long infrarenal aortic neck and normal diameter non-tortuous iliac arteries may be suitable for both endovascular and open techniques. However, indications for open surgery are becoming increasingly unclear nowadays due to short-term gains in morbidity and mortality. Exact aortic anatomical morphologies optimum for open or endovascular techniques remains unclear. As graft technology evolves, possibilities for endovascular options are expanding. Currently, establishing optimum treatment plans for complicated abdominal aortic aneurysm (little or no infrarenal neck) is difficult without considering general fitness of the patient. Hence, two sets of possible postoperative complications and follow-up protocols must be explained to patients before either approach. Complicating matters is the optimum surgical approach used for any open repair. The standard approach for open abdominal aortic aneurysm surgery has been transperitoneal as this provides excellent access to the infrarenal aorta and iliac arteries. However, although less commonly used, the retroperitoneal approach has advantages particularly when location of proximal aortic disease indicates suprarenal clamp might be optimum. This paper scrutinises benefits of the retroperitoneal approach performed purely for anatomical reasons where stent graft may be considered complicated. Also, long-term outcomes are examined in terms of endo-leak and subsequent development of true and false aneurysm following both endovascular and open repair.

Polymer based endografts have improved rates of proximal aortic neck dilatation and migration

BACKGROUND

Proximal aortic neck dilatation (PND) affects a considerable proportion of patients undergoing endovascular aneurysm repair (EVAR) and is associated with increased rates of type I endoleak (EL1), migration, and reinterventions. Although there are numerous studies investigating PND following the placement of endografts that utilize self-expanding stent (SES) technology, there are few reports for patients treated with endografts that utilize polymer-filled rings. The purpose of this study is to examine PND and graft migration after EVAR with the Ovation stent graft.

METHODS

The study comprised patients who underwent EVAR as part of the prospective, international, multicenter Ovation stent graft trial. A clinical events committee adjudicated adverse events through 1 year, an independent imaging core laboratory analyzed imaging through 5 years, and a data safety and monitoring board provided study oversight. Neck diameter was measured at the level of the lowest renal artery. PND was defined as neck enlargement of 3 mm or more. Graft migration was defined as distal movement >10 mm or movement ≤10 mm when resulting in secondary intervention.

RESULTS

A total of 238 patients received this device during the study period. Patients were predominantly male (81%), with a mean age of 73 ± 8 years. Median follow-up was 58 months (IQR 36-60). Almost half the patients (110 patients, 46%) had challenging anatomy; defined as outside the instructions for use (IFU) with other commercially available stent grafts. 41 patients (17.2%) had a proximal neck length <10 mm and 93 (39%) had a minimum access vessel diameter <6 mm. The technical success rate was 100%. The 1-, 3- and 5-year overall survival rates were 96.6%, 86.2% and 74.9%, respectively. The immediate postoperative proximal neck diameter ranged from 16 mm to 31 mm with a mean of 22.4 ± 3 mm. During follow-up, ten patients (4.2%) developed PND. Freedom from PND estimates at 1, 3 and 5 years were 97.7%, 96%, and 93.6%, respectively. None of the patients developed endograft migration.

CONCLUSIONS

The use of the Ovation stent graft was associated with low rates of PND despite challenging neck anatomy in 17% of patients. No graft migration was observed. The design of this endograft may explain its superiority to SES in preventing neck dilatation and migration even in patients with challenging neck anatomy. This is important, as we continue to see significant late failures of EVAR due to proximal neck degeneration.

Long-term outcomes and interventions of postoperative type 1a endoleak following elective endovascular aortic aneurysm repair

OBJECTIVE

This study evaluated the incidence and long-term outcomes of postoperative type 1a endoleak (PT1a) following endovascular aortic aneurysm repair (EVAR).

METHODS

A retrospective review of consecutive aorto-iliac EVARs performed at a single institution from June 2006 to June 2012 was conducted. Patients with PT1a were identified by postoperative imaging and compared with those who did not develop a PT1a. Late outcomes were also studied of a subset of patients with PT1a who had persistent intraoperative type 1a endoleak (iT1a) on completion angiogram during EVAR that had resolved on initial follow-up imaging.

RESULTS

Three hundred eighty-nine patients underwent EVAR with median follow-up of 87 months (interquartile range, 64-111 months). The incidence of PT1a was 8.2% (n = 32) with a median follow-up of 74 months (interquartile range, 52-138 months). Compared with the total cohort, those who developed PT1a were statistically more likely to be female (32% vs 17%; P = .03) and have a higher all-cause mortality (71% vs 40%; P < .01) and aneurysm-related mortality (15.6% vs 1.7%; P < .01). Median time to presentation was 52 months. Of the 32 patients with PT1a, five (15.6%) presented with aortic rupture, of which three underwent extension cuff placement, one had open graft explant, and one declined intervention. Six patients in total (18.7%) declined intervention; five of these died of nonaneurysmal causes and one remains alive. Of the 26 patients with PT1a who had intervention, 21 (80.7%) showed resolution of PT1a, and five (19.2%) had recurrence. For patients with recurrent PT1a, two had resulting aneurysm-related mortality, two endoleaks resolved after relining with an endograft, and one patient declined intervention but remains alive. Patients with PT1a who had intervention with resolution showed no significant difference in median survival estimates (140.0 months) compared with the remaining EVAR cohort (120.0 months; P = .80). Within the PT1a cohort, 6 (18.7%) had also experienced iT1a with a mean time to presentation of the late PT1a of 45 months. iT1a was associated with a significantly increased likelihood of developing a PT1a (P < .01) and decreased median survival (P < .01), but there was no known aneurysm-related mortality.

CONCLUSIONS

Development of PT1a following elective EVAR is associated with increased all-cause and aneurysm-related mortality and presents an average of 52 months postoperatively. This underscores the importance of long-term surveillance. Patients with PT1a who had a successful intervention showed no significant difference in median survival. Those with iT1a had a higher risk for PT1a compared with the EVAR cohort overall and had decreased median survival, without increased aneurysm-related mortality.

A Five-Year Computed Tomography Follow-up Study of Proximal Aortic Neck Dilatation After Endovascular Aortic Repair Using Four Contemporary Types of Endograft

OBJECTIVE

This study analysed the progression of proximal aortic neck diameter in patients with asymptomatic abdominal aortic aneurysms, treated by endovascular aortic repair using four different, contemporary types of endograft.

METHODS

This is a retrospective study of four cohorts of 30 patients presenting with asymptomatic abdominal aortic aneurysms and treated with endovascular aortic repair using four different types of contemporary endografts, namely Endurant® (Medtronic), Excluder® (W.L. Gore), Zenith® (Cook Medical) and Ovation® (Endologix) endografts. Patients' demographics and aortic aneurysm measurements, including suprarenal aortic, proximal infrarenal neck and maximum aortic aneurysmal diameter, were gathered from the patients' electronic medical records, pre- and post-interventional computed tomography studies, respectively. Diameter measurements were modelled as a function of endograft type; an interaction test was used to test whether the evolutions over time were different between the four types of endograft.

RESULTS

Suprarenal aortic diameter increased over time (P = 0.0235) and maximum aortic aneurysm diameter decreased over time (P = 0.0008) in the four types of endograft. The progressive increase in proximal neck diameter from preoperative baseline up to five years of follow-up was 1.20 mm for Endurant (P = 0.0054), 1.72 mm for Ovation (P = 0.0006), 1.14 mm for Excluder (P = 0.0102) and 2.83 mm for Zenith (P < 0.0001), respectively. Five patients (4%) presented with a late-type 1a endoleak: Endurant (n = 1); Ovation (n = 2) and Zenith (n = 2).

CONCLUSION

All endografts were associated with a progressive dilatation of the proximal aortic neck over a time interval of five years and may be associated with late-type 1a endoleak.

Visceral segment aortic thrombus is associated with proximal aortic degeneration after infrarenal abdominal aortic aneurysm repair

OBJECTIVE

To identify predictors of aortic aneurysm formation at or above an infrarenal abdominal aortic aneurysm repair.

METHODS

A total of 881 infrarenal abdominal aortic aneurysm repairs were identified at a single institution from 2004 to 2008; 187 of the repairs were identified that had pre-operative and post-operative computed tomography imaging at least one year or greater to evaluate for aortic degeneration following repair. Aortic diameters at the celiac, superior mesenteric, and renal arteries were measured on all available computed tomographic scans. Aortic thrombus and calcification volumes in the visceral and infrarenal abdominal aortic segments were calculated. Multivariable modeling was used with log transformed variables to determine potential predictors of future aortic aneurysm development after infrarenal abdominal aortic aneurysm repair.

RESULTS

Of the 187 patients in the cohort, 100 had an open abdominal aortic aneurysm repair while 87 were treated with endovascular repair. Proximal aortic aneurysms developed in 26% (n = 49) of the cohort during an average of 72 ± 34.2 months of follow-up. After multivariable modeling, visceral segment aortic thrombus on pre-operative computed tomography imaging increased the risk of aortic aneurysm development above the infrarenal abdominal aortic aneurysm repair within both the open abdominal aortic aneurysm (hazard ratio 2.04, p = 0.033) and endovascular repair (hazard ratio 3.31, p = 0.004) cohorts. Endovascular repair was independently associated with a higher risk of future aortic aneurysm development after infrarenal abdominal aortic aneurysm repair when compared to open abdominal aortic aneurysm (hazard ratio 2.19, p = 0.025).

CONCLUSIONS

Visceral aortic thrombus present prior to abdominal aortic aneurysm repair and endovascular repair are both associated with an increased risk of future proximal aortic degeneration after infrarenal abdominal aortic aneurysm repair. These factors may predict patients at higher risk of developing proximal aortic aneurysms that may require complex aortic repairs.

Risk Factors, Dynamics, and Clinical Consequences of Aortic Neck Dilatation after Standard Endovascular Aneurysm Repair

OBJECTIVE

Aortic neck dilatation (AND) occurs after endovascular aneurysm repair (EVAR) with self expanding stent grafts (SESs). Whether it continues, ultimately exceeding the endograft diameter leading to abdominal aortic aneurysm (AAA) rupture, remains uncertain. Dynamics, risk factors, and clinical relevance of AND were investigated after EVAR with standard SESs.

METHODS

All intact EVAR patients treated from 2000 to 2015 at a tertiary institution were included. Demographic, anatomical, and device related characteristics were investigated as risk factors for AND. Outer to outer diameters were measured at a single standardised aortic level on reconstructed computed tomography (CT) images.

RESULTS

A total of 460 patients were included (median follow up 5.2 years, interquartile range [IQR] 3.0, 7.7 years; CT imaging follow up 3.3 years, IQR 1.3, 5.4). Baseline neck diameter was 24 mm (IQR 22, 26) and increased 11.1% (IQR 1.5%, 21.9%) at last CT imaging. Endograft oversizing was 20.0% (IQR 13.6, 28.0). AND was greater during the first year (5.2% [IQR 0, 11.7]) decreasing subsequently (two to four years to 1.4%/year [IQR 0.0, 4.5%], p ≤ .001) and was associated with suprarenal fixation endografts (t value = 7.9, p < .001) and oversizing (t value = 4.4, p < .001). AND exceeding the endograft was 3.5% (95% CI 2.2% - 4.8%) and 14.4% (95% CI 11.0% - 17.8%) at five and eight years, respectively. Excessive AND was associated with baseline neck diameter (OR 1.2/mm, 95% CI 1.05 - 1.41) while the Excluder endograft had a protective effect (OR 0.15, 95% CI 0.04 - 0.58). Excessive AND was associated with type 1A endoleak (HR 3.3, 95% CI 1.1 - 9.7) and endograft migration > 5 mm (HR 3.1, 95% CI 1.4 - 6.9).

CONCLUSION

AND after EVAR with SES is associated with endograft oversizing and radial force but decelerates after the first post-operative year. Baseline aortic neck diameter and suprarenal stent bearing endografts were associated with an increased risk of AND beyond nominal stent graft diameter. However, it remains unclear whether patient selection, differences in endograft radial force or the suprarenal stent are accountable for this difference.

Endograft platform does not influence aortic neck dilatation after infrarenal endovascular aneurysm repair with primary endostapling

OBJECTIVES

Aortic endografts used for endovascular aneurysm repair (EVAR) are based on varying skeletal platforms such as stainless steel or nitinol stents, using radial force applied to seal at the aneurysm neck, and varying proximal fixation methods, applying either suprarenal or infrarenal fixation. This study assesses whether varying skeleton/fixation platforms affect neck-related outcomes after primary endostapling with Heli-FX EndoAnchors at EVAR.

METHODS

Retrospective analysis of a prospective database of infrarenal EVAR undertaken at a single centre. Chimney-EVAR, secondary cases were excluded. Primary outcomes analysed included neck diameter evolution from pre-EVAR to latest imaging follow-up, including a comparison of stent platforms to see if there was any outcome difference between those using stainless steel or nitinol, as also freedom from type I endoleakage and migration. Secondary outcomes assessed included average number of EndoAnchors, and sac size patterns before and after EVAR.

RESULTS

A total of 101 patients underwent endostapled infrarenal EVAR between September 2013 and March 2020. After exclusion of ineligible patients, 84 patients (76 male, 8 female, age 73.7 ± 7.8 years) were available for analysis. 57/27 endografts used suprarenal/infrarenal fixation, whilst 16/68 devices were based on stainless steel/nitinol platforms, respectively. Mean oversizing was higher for stainless steel/suprarenal fixation endografts (p = 0.02). A total of 582 EndoAnchors were deployed, averaging 7 ± 2 per patient. Median neck diameter was 25 mm (IQR 22-31) with 22 necks having non-parallel morphology (conical, tapered or bubble). Median follow-up period was 28.5 (IQR 12-43) months. Neck evolution studies suggested aortic neck dilatation of 5 ± 4 mm (p <0.001, paired T-test), independent of platforms employed (p = NS, ANOVA). There was no endograft migration; one immediate post-EVAR endoleak settled by eight weeks. There was a mean 5.7 ± 8.2 mm sac size reduction (p < 0.001, paired T-test).

CONCLUSION

Aortic neck dilatation occurs after EVAR with primary endostapling, but the process may be independent of stainless steel/nitinol platforms, possibly due to the attenuating effect of EndoAnchors. Adjunct aneurysm neck fixation by primary endostapling prevents migration regardless of whether suprarenal/infrarenal fixation is the primary fixative method. Device platform choice therefore may be left to the operator discretion if primary endostapling is applied at EVAR. Freedom from complications such as migration and endoleakage in the intermediate term suggests a higher level of 'tolerance' to aortic neck dilatation with primary endostapling. We would therefore suggest routine usage of EndoAnchors at EVAR when not otherwise contraindicated.

Changes in Neck Angle, Neck Length, Maximum Diameter, Maximum Area and Thrombus after Endovascular Aneurysm Repair

Purpose

The correlation of initial anatomy of the aneurysm, aneurysmal remodeling and endoleaks is controversial. We performed a retrospective study to measure aneurysmal remodeling with time, and to assess the structural changes in the aneurysm neck after endovascular aneurysm repair (EVAR).

Materials and Methods

From January 2013 to February 2018, 108 patients with abdominal aortic aneurysms (AAA) underwent EVAR. Follow-up computed tomography images were available for 90 patients. Anatomic variables, including the neck angle, neck length, maximal diameter, maximal area, and thrombus volume were measured. Temporal changes were measured preoperatively, immediate postoperatively (within 1 week after EVAR), and at 6 months, 1 year, and 2 years post-EVAR. Correlation between the variables according to the temporal changes and presence of type Ia endoleaks (T1aE) was analyzed.

Results

The mean follow-up period was 10.63±20.34 months. Significant decreases in neck angle and length occurred immediately postoperative (P<0.001 and 0.036). Maximum diameter decreased at 6 months post-EVAR (P=0.003), but no significant changes in the maximal area occurred over time (P=0.142). Thrombus volume in the aneurysm sac increased immediately post-EVAR (P=0.008). There was no significant relationship between T1aE and neck changes in the group and time comparison (P=0.815 and 0.970).

Conclusion

Changes in neck angle, length and thrombus volume occurred immediately after EVAR, whereas a change in the maximum diameter of the AAA was noted 6 months after EVAR. Preoperative anatomic variables related with T1aE were not found.

Dilatation of Aortic Neck and Common Iliac Arteries after Open Repair of Abdominal Aortic Aneurysms: Long-Term Follow-Up According to Aortic Reconstruction Configuration

BACKGROUND

Several studies in the literature report continued proximal aorta and distal iliac artery dilatation after surgical correction of an abdominal aortic aneurysm (AAA). The purpose of this study is to evaluate these findings, in a South American population, and relate them to the type of configuration of the open procedure aortic reconstruction.

METHODS

This is a retrospective review of ultrasonographic follow-up of patients submitted to open repair of AAA from 1989 to 2013, reporting proximal aorta dilatation (≥3 cm) and distal iliac artery dilatation (≥1.5 cm).

RESULTS

A total of 155 patients were included. Life-table freedom at the intervals 11 < 15 years and ≥15 years were 47% and 23% for proximal dilatation and 63% and 38% for distal iliac arteries dilatation, respectively. There were more proximal and distal dilatations in patients submitted to more extensive aortic reconstructions (aorto-aortic 13% and 22% vs aorto-bilateral common iliacs 27% and 8% vs aorto-unilateral or bilateral external iliacs 27% and 32% and aorto-femoral 67% and 0%) P < 0.0001. Juxtarenal anastomosis was also correlated with more proximal dilatations (42% vs 21%, P = 0,046). There were two proximal and three distal anastomosis pseudoaneurysms.

CONCLUSIONS

The presence of more extensive degenerative disease at the time of operation, requiring juxtarenal or more distal iliac reconstructions, may pose an increased risk of proximal aorta and iliac artery dilatation during follow-up. This study corroborates that significant changes are found after 7 to 10 years of the operation, reinforcing the need for long-term monitoring.

Quantification of suprarenal aortic neck dilation after fenestrated endovascular aneurysm repair

OBJECTIVE

Suprarenal aortic neck dilation (AND) after fenestrated endovascular aneurysm repair (FEVAR) with commercially available devices has not yet been well characterized. The aim of this study was to measure diameter changes in the supravisceral aorta after FEVAR.

METHODS

This is a single-center retrospective review involving patients with juxtarenal aneurysms treated with Cook ZFEN devices (Cook Medical, Bloomington, Ind). Patients with at least 1 year of cross-sectional radiologic follow-up were included. AND was defined as ≥3 mm at any measured location. Aortic diameter, defined as the average outer to outer diameter on three-dimensional centerline imaging, was measured at seven locations along the length of the ZFEN device from the proximal fixation struts to the bottom of the second seal stent. The first postoperative CT scan (≤1 month) served as a baseline from which subsequent measurements at annual intervals were compared.

RESULTS

A total of 43 patients who underwent FEVAR from 2012 to 2018 met inclusion criteria, with a total of 119 target vessels (83 renal stents, 41 superior mesenteric artery scallops or large fenestrations). Mean follow-up time was 30.3 months. Any AND was found to occur in 32 (74.4%) patients. Aortic diameter dilation at latest follow-up was found to occur at all measured locations from the top of the fixation struts (1.9 ± 2.4 mm; P < .0001) to the middle of the second seal stent (1.3 ± 3.8 mm; P < .01). Diameter growth was most pronounced in the middle of the first seal stent, with mean AND of 3.6 ± 3.2 mm. At this location, the aorta experienced nearly linear annual growth of 0.99 mm (95% confidence interval, 0.7-1.28 mm) per year. Increasing device oversizing relative to the native visceral aorta was the strongest predictor of postoperative neck diameter growth (1.34 mm per 10% increase in oversizing; P = .02), whereas increasing proximal seal length was protective of growth (-1.82 mm per 10-mm increase in seal length; P = .016). Proximal seal lengths ≥3 cm were associated with less neck dilation compared with <3 cm (2.6 mm vs 4.9 mm; P = .022). Type IA endoleak in this cohort was rare (n = 1) and not associated with AND (P = .256).

CONCLUSIONS

Dilation of the suprarenal aorta is a common finding in midterm follow-up after FEVAR and not associated with proximal endoleak. Aggressive device oversizing is predictive of dilation, whereas longer seal lengths are associated with less dilation along the suprarenal seal zone. These results support the continued use of FEVAR for juxtarenal aneurysms, particularly in patients in whom ≥3 cm of healthy seal length can be obtained.

Consecutive failing proximal landing zones

We report the case of a 77-year-old man who presented with successive aortic aneurysms during a 12-year period. He was first treated in 2006 for an abdominal aortic aneurysm with a bifurcated endograft, then in 2016 for a tender type IV thoracoabdominal aortic aneurysm with a proximal aortic cuff with in situ laser fenestrations. He presented in 2018 with a 9-cm distal thoracic aorta aneurysm managed by an off-the-shelf t-Branch endograft (Cook Medical, Bloomington, Ind). The perioperative course was uneventful, and 6-month follow-up computed tomography scan has shown freedom from endoleaks and branch patency. This case illustrates that apparently “healthy” aortic necks can degenerate after endovascular aneurysm repair.

Geometric Remodeling of the Perirenal Aortic Neck at and Adjacent to the Double Sealing Ring of the Anaconda Stent-Graft After Endovascular Aneurysm Repair

Purpose: To evaluate if the radial force of the double sealing ring of the Anaconda stent-graft induces dilatation in the perirenal aortic neck adjacent to the rings. Materials and Methods: This study evaluated the serial electrocardiogram-gated computed tomography scans of 15 abdominal aortic aneurysm patients (mean age 72.8±3.7 years; 14 men) who were treated electively using an Anaconda stent-graft. Follow-up scans were conducted before discharge and at 1, 6, 12, and 24 months after endovascular repair. Diameter and area were assessed perpendicular to the aortic centerline along the perirenal aortic neck, which was subdivided into 3 zones: the suprastent, the stent, and the infrastent zones. Measurements were performed independently by 2 experienced observers using dedicated 3-dimensional image processing software. Results: Between discharge and the 2-year follow-up the diameter and area remained stable in the suprastent zone [average diameter change: −0.1±0.4 mm (−0.4%±1.7%), p=0.893; average area change: −2.9±17.2 mm² (−0.7%±3.4%), p=0.946], increased in the stent zone [average diameter change: +1.9±1.0 mm (+7.3%±4.0%), p<0.001; average area change: +84.3±48.3 mm² (+15.5%±8.7%), p<0.001], and diverged in the infrastent zone [average diameter change: −0.8±2.2 mm (−2.3%±7.4%), p>0.99; average area change: −34.6±102.3 mm² (−4.1%±14.8%), p>0.99; increased in 4 patients, decreased in 9 patients]. Conclusion: After Anaconda implantation the infrarenal aortic neck accommodated to the expansion of the sealing rings at the stent zone. Below the stent zone the neck diameter decreased in the majority of patients, while an increase was related to downstream displacement of the main body. A decrease in size in the infrastent zone may contribute to durable sealing and fixation. A personalized follow-up scheme based on geometric neck remodeling should be feasible if our observations are confirmed in larger, long-term studies.

Five-year results of endovascular abdominal aortic aneurysm repair with the Ovation abdominal stent graft

OBJECTIVE

Endovascular abdominal aortic aneurysm repair (EVAR) has been rigorously compared with open repair for the treatment of abdominal aortic aneurysms in randomized trials and observational studies, but a comparison of individual devices is lacking, and single-device registries and trials are limited by small sample size. Here we report a descriptive analysis of the Effectiveness of Custom Seal with Ovation: Review of the Evidence (ENCORE) database, pooled results of multiple studies evaluating the midterm results of EVAR with the Ovation Abdominal Stent Graft Platform.

METHODS

This is a retrospective analysis of the ENCORE database, a cohort of patients undergoing EVAR with the Ovation platform composed of pooled, prospectively collected data from 1296 patients from five clinical trials and the prospectively maintained European Union Post-Market Registry. The primary outcomes were 5-year rates of type IA and type I or III endoleak. Secondary outcomes included were 30-day mortality, 30-day major adverse event, technical success (successful deployment of the aortic body and iliac limbs), as well as 5-year survival, and freedom from aneurysm-related mortality, type II endoleak, device-related intervention, aneurysm rupture, sac expansion, and conversion to open repair.

RESULTS

A total of 1296 patients were included in the analysis. The average age was 73 ± 8 years and 81% of patients were male. Fifty percent of patients had complex aortic anatomy, (neck length <10 mm, neck diameter >28 mm, neck angle >60°, reverse neck taper >10%, distal common iliac artery diameter <10 mm, or external iliac artery diameter <6 mm). Technical success was 99.7%. Thirty-day mortality was 0.3%, 30-day rate of major adverse event was 1.6%, and polymer leak rate was 0.2%. Freedom from type IA endoleak at 1, 3, and 5 years was 97.6%, 97.1%, and 95.8%, respectively; type I or III endoleak at 1, 3, and 5 years was 96.9%, 95.7%, and 94.0%, respectively. Freedom from device-related reintervention at 1, 3, and 5 years was 96.2%, 94.4%, and 92.4% and primary freedom from sac expansion was 97.0% at 1 year, 90.3% at 3 years, and 84.9% at 5 years. Freedom from all-cause mortality and aneurysm-related mortality at 5 years were 78.9% and 99.3%, respectively.

CONCLUSIONS

This analysis of the ENCORE database demonstrates that EVAR with the Ovation platform has favorable midterm durability evidenced by successful aneurysm exclusion and 5-year freedom from aneurysm-related mortality.

Current evidence on aortic remodeling after endovascular repair

Anatomical changes after endovascular repair (EVAR) of abdominal aortic aneurysms (AAAs) are thoroughly studied as they could affect the long-term postoperative outcome. The aim of the present study was to review the literature and summarize the recent data regarding the aortic remodeling and its clinical significance. A continuous aortic neck expansion is observed after EVAR and is more rapid at the first month and during the third postoperative year. This aortic neck dilation is not influenced by the type of proximal stent-graft fixation, is comparable to open surgical aneurysm repair and is most probably related with the natural progression of aneurismal disease. Aortic neck angulation reduces significantly immediately after EVAR and then continues to reduce slowly and gradually. Neck angulations ≥60° have a greater reduction compared to neck angulations <60°. An expansion of the common iliac arteries at the distal landing zone is also observed after EVAR and is more prominent in the first six postoperative months. A postoperative increase of the distance between superior mesenteric artery and iliac bifurcations (aortoiliac elongation) is described and is associated with increased type I endoleaks and reinterventions. The aneurysm sac diameter most frequently reduces after EVAR in absence of an endoleak and this aneurysm sac regression has been associated with the stent-graft type.

Postoperative Aortic Neck Dilation: Myth or Fact?

The abdominal aorta is the most common site of an aortic aneurysm. The visceral and most proximal infrarenal segment (aneurysm neck) are usually spared and considered more resistant to aneurysmal degeneration. However, if an abdominal aortic aneurysm (AAA) is left untreated, the natural history of the aortic neck is progressive dilatation and shortening. This may have significant implications for patients undergoing endovascular repair of AAAs (EVAR) as endograft stability and integrity of the repair are dependent on an intact proximal seal zone. Compromised seal zones, caused by progressive diameter enlargement and foreshortening of the aortic neck, may lead to distal endograft migration, type Ia endoleak, aortic sac repressurization, and, ultimately, aortic rupture.

Evolution of the Proximal Sealing Rings of the Anaconda Stent-Graft After Endovascular Aneurysm Repair

Purpose: To provide insight into the evolution of the saddle-shaped proximal sealing rings of the Anaconda stent-graft after endovascular aneurysm repair (EVAR). Methods: Eighteen abdominal aortic aneurysm patients were consecutively enrolled in a single-center, prospective, observational cohort study (LSPEAS; Trialregister.nl identifier NTR4276). The patients were treated electively using an Anaconda stent-graft with a mean 31% oversizing (range 17–47). According to protocol, participants were to be followed for 2 years, during which 5 noncontrast electrocardiogram-gated computed tomography scans would be conducted. Three patients were eliminated within 30 days (1 withdrew, 1 died, and a third was converted before stent-graft deployment), leaving 15 patients (mean age 72.8±3.7 years; 14 men) for this analysis. Evolution in size and shape (symmetry) of both proximal infrarenal sealing rings were assessed from discharge to 24 months using dedicated postprocessing algorithms. Results: At 24 months, the mean diameters of the first and second ring stents had increased significantly (first ring: 2.2±1.0 mm, p<0.001; second ring: 2.7±1.1 mm, p<0.001). At 6 months, the first and second rings had expanded to a mean 96.6%±2.1% and 94.8%±2.7%, respectively, of their nominal diameter, after which the rings expanded slowly; ring diameters stabilized to near nominal size (first ring, 98.3%±1.1%; second ring, 97.2%±1.4%) at 24 months irrespective of initial oversizing. No type I or III endoleaks or aneurysm-, device-, or procedure-related adverse events were noted in follow-up. The difference in the diametric distances between the peaks and valleys of the saddle-shaped rings was marked at discharge but became smaller after 24 months for both rings (first ring: median 2.0 vs 1.2 mm, p=0.191; second ring: median 2.8 vs 0.8 mm; p=0.013). Conclusion: Irrespective of initial oversizing, the Anaconda proximal sealing rings radially expanded to near nominal size within 6 months after EVAR. Initial oval-shaped rings conformed symmetrically and became nearly circular through 24 months. These findings should be taken into account in planning and follow-up.

No Difference in Neck Enlargement for Patients Treated With Double Proximal Self-Expandable Suprarenal Fixation Endografting

INTRODUCTION

Neck enlargement is well described in patients treated with self-expandable endografts for abdominal aortic aneurysms. Double endografting (ie, overlapping of stent grafts) occurs in patients with proximal cuffs or bifurcated to monoiliacal configuration conversions. When the aortic neck of patients receives 2 suprarenal fixation endografts, it may behave differently in terms of radial force and interaction of additional suprarenal stents extending to the visceral aorta.

METHODS

We performed a retrospective study comparing 2 groups. Group 1 included 18 patients treated with 2 proximal self-expandable endografts. Group 2 included 17 patients treated with 1 self-expandable endograft who were consecutively treated during the period of treatment in group 1. Neck measurements were analyzed in both groups preoperatively and in the last computed tomography scan during follow-up. Suprarenal, interrenal, juxtarenal, and infrarenal (at 5 and 10 mm) diameters, as well as interrenal and infrarenal (5 mm) areas, were measured.

RESULTS

There was no significant difference in baseline characteristics, initial neck measurements, and aneurysmal sac evolution including endoleaks between the groups. Both groups showed neck enlargement. Group comparisons of all parameters in posttreatment neck measurements showed no statistical change. Univariate analysis showed oversizing to be significant in interrenal diameter and area and infrarenal at 10 mm diameter; however, 2-way analysis of variance analysis showed that the interaction between oversizing and the number of stent grafts was not significant.

CONCLUSION

Neck enlargement occurs in patients with self-expandable endografts with a tendency to reach the size of the endograft in the long term. Double endografting seems to interact in the same way as simple endografting in the aortic neck. Although the main limitation of our study lies in the small sample size, the presence of an additional "double" stent graft does not appear to result in any differences in aortic neck dilatation when compared to a single stent graft.

Proximal Aortic Neck Progression: Before and After Abdominal Aortic Aneurysm Treatment

Several risk factors including short or highly angulated proximal aortic neck have been associated with long-term outcomes after endovascular or open abdominal aortic aneurysm (AAA) repair. However, research data have emerged recently concerning the behavior of proximal aortic neck, and several authors have tried to evaluate this behavior after endovascular or open repair. Additionally, computed tomography angiography (CTA) remains the golden standard for detecting and observing the morphology of an AAA, both before and after treatment. Moreover, the question of whether the proximal neck’s progression independently affects postoperative morbidity and reintervention risks still remains. Therefore, this focused review aims to present all relevant data on the behavior of an AAAs neck, based on CTA imaging before and after repair, in order to produce useful conclusions for future clinical practice.

A Systematic Review of Proximal Neck Dilatation After Endovascular Repair for Abdominal Aortic Aneurysm

Purpose: To provide an updated systematic literature review and summarize current evidence on proximal aortic neck dilatation (AND) after endovascular aneurysm repair (EVAR). Methods: A review of the English-language medical literature from 1991 to 2015 was conducted using MEDLINE and EMBASE to identify studies reporting AND after EVAR. Studies considered for inclusion and full-text review fulfilled the following criteria: (1) reported AND after EVAR, (2) included at least 5 patients, and (3) provided data on AND quantification. The search identified 26 articles published between 1998 and 2015 that encompassed 9721 patients (median age 71.8 years; 9439 men). Results: AND occurred in 24.6% of patients (95% CI 18.6% to 31.8%) over a period ranging from 15 months to 9 years after EVAR. No significant dilatation of the suprarenal part of the aorta was reported by most studies. The incidence of combined clinical events (endoleak type I, migration, reintervention during follow-up) was higher in the AND group (26%) when compared with 2% in the group without AND (OR 28.7, 95% CI 5.43 to 151.67, p<0.001). Conclusion: AND affects a considerable proportion of EVAR patients and was related to worse clinical outcome, as indicated by increased rates of type I endoleak, migration, and reinterventions. Future studies should focus on a better understanding of the pathophysiology, predictors, and risk factors of AND, which could identify patients who may warrant a different EVAR strategy and/or a closer post-EVAR surveillance strategy.

Nellix EndoVascular Aneurysm Sealing System: Device description, technique of implantation, and literature review

Clinical outcome reports document that from 30% to 60% of endovascular aneurysm repair procedures are performed outside of US Food and Drug Administration-approved Instruction for Use, or "off label." Endovascular aneurysm repair performed outside of Instruction for Use has a significantly higher rate of device failure, potentially requiring device reintervention and even planned or emergent explant. The Nellix device has the potential to reduce the rate of aneurysm device failure through its novel design. The objective of this article was to introduce the Nellix EndoVascular Aneurysm Sealing System and indications for use and describe the technique of implantation. We describe various modes of endovascular aneurysm repair failure and how the Nellix system can reduce these unplanned adverse outcomes. Additional clinical applications and theoretical shortcomings of endovascular aneurysm sealing devices are detailed.

Length of abdominal aortic aneurysm and incidence of endoleaks type II after endovascular repair

OBJECTIVE

To evaluate the predicting factors for the development of endoleak type II, its frequency and influencing factors after elective endovascular repair (EVAR) of infrarenal abdominal aortic aneurysms (AAA).

METHODS

Data were prospectively collected in a unicenter observational study (tertiary center of [endo-] vascular surgery) and retrospectively evaluated in patients who had undergone elective EVAR of AAA. Vascular (lumbar arteries (LA) and inferior mesenteric artery, aneurysm) and general patient (habits, medication, basic diseases) as well as procedural characteristics, were analyzed for their association with the development of endoleak type II. Pre and postinterventional computed tomography (CT) scans were evaluated for aneurysm anatomy, in particular, postinterventional growth or shrinkage as well detection of an endoleak of each type.

RESULTS

The study cohort included 82 patients (mean age, 72 (52-87) years; 77 men, 93.9%) throughout 36 months. The median follow-up period was 29.5 months (range, 1-57). Overall, 51 endoleaks type II (62.2%) were identified at any time during the postinterventional follow-up period. In the Cox regression, AAA length was the only significant predictor (P = 0.024; hazard ratio (HR), 1.07; 95% confidence interval (CI), 1.01-1.14). Thirteen patients (15.8%) underwent at least one secondary intervention. Aneurysm growth was observed in four patients because of an endoleak type II (4.9%). No AAA rupture occurred in association with an isolated endoleak type II.

CONCLUSION

The preoperative AAA length (correlating with the number of LA) can be considered a risk factor for postinterventional occurrence of endoleak type II prompting to greater attention and possible preemptive therapy.