The incidence and effect of noncylindrical neck morphology on outcomes after endovascular aortic aneurysm repair in the Global Registry for Endovascular Aortic Treatment

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.

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.

Predictors of Aneurysm Sac Shrinkage Utilizing a Global Registry

BACKGROUND

Aneurysm sac remodeling is a complex multifactorial process with unknown factors influencing sac regression after endovascular aortic aneurysm repair (EVAR). We sought to identify factors associated with this process by analyzing data obtained from patients treated with the GORE EXCLUDER endovascular aneurysm repair (EVAR) endoprosthesis from December 2010 to October 2016 enrolled in the Global Registry for Endovascular Aortic Treatment (GREAT).

METHODS

All patients enrolled in GREAT with three years CT angiography (CTA) follow-up in each of the three successive years after EVAR were included. The percentage of sac size reduction toward device diameter was calculated and used as a surrogate for sac regression with the formula used being: sac size reduction = ((AAA baseline diameter - AAA diameter at follow-up)/(AAA baseline diameter - device diameter))∗100. The cohort was divided into two groups in accordance with the percentage of aneurysm sac reduction at three years; one with the top quartile of patients and the other with the lowest three quartiles. Demographic and procedural variables were analyzed using univariate and regression modeling to determine factors predictive of sac regression.

RESULTS

There were 3265 subjects enrolled with follow-up as of May 2018 of which 526 (16.2%) had three years of CTA surveillance. Overall aneurysm sac size decreased from a mean of 58.0 mm (Std Dev: 10.4, range: 34.2, 100.0) to a mean of 49.3 mm (Std Dev: 14.1, range: 0, 140) for a percentage reduction toward device diameter of a mean 28.2% (Std Dev: 39.0, range: -103.7, 183.9). On multivariate logistic regression model; two factors proved to be statistically significant contributors to a larger percentage reduction in aneurysm sac: a conical neck (odds ratio [OR] = 1.64, P-value = 0.023) and a larger proximal device diameter (OR = 1.09, P-value = 0.023). On the other hand, two factors were negative predictors of sac shrinkage, namely: old age (OR = 0.96, P-value = 0.002) and larger baseline aneurysm sac diameter (OR = 0.98, P-value = 0.028).

CONCLUSIONS

Aneurysms with conical necks and larger proximal device neck diameters have an increased percentage change in sac size over time after EVAR. Older age and larger initial diameters of aneurysms were negatively associated with percentage change in sac size as well as sac regression. Further study is needed to determine the clinical utility of these observations and applicability across multiple endoprosthesis platforms.

Sex-Related Outcomes After Endovascular Aneurysm Repair Within the Global Registry for Endovascular Aortic Treatment

BACKGROUND

Abdominal aortic aneurysms (AAAs) are more common in men. However, women have been shown to have more short- and long-term adverse outcomes after endovascular aneurysm repair. This disparity is thought to be multifactorial, including anatomical differences, hormonal differences, older age of presentation, and a greater degree of preoperative comorbidities.

METHODS

A retrospective analysis that included data for 3,758 patients from the Global Registry for Endovascular Aortic Treatment (GREAT) was conducted. Patients were recruited into GREAT between August 2010 and October 2016 and received the Gore Excluder stent graft for infrarenal AAAs repair. Cox multivariate regression analyses were performed to analyze any reintervention and device-related intervention rates.

RESULTS

Of the 3,758 patients, 3,220 were male (mean age 73 years) and 538 were female (mean age 75 years). Women had higher prevalence rates of chronic obstructive pulmonary disease (P < 0.0001) and renal insufficiency (P = 0.03), whereas men had higher rates of cardiovascular comorbidities. The AAAs in women were smaller in diameter with shorter and more angulated necks. Women did not experience a significantly higher rate of endoleaks but did exhibit higher reintervention rates, including reintervention for device-related issues. In terms of mortality, aorta-related mortality was most prevalent within the first 30 days after procedure in both sexes.

CONCLUSIONS

Women were treated at an older age and had a more hostile aneurysmal anatomy. Although the mortality rates were lower in women, they had significantly higher rates of reintervention, and thus higher morbidity rates after endovascular aneurysm repair.