Remodeling of aortic aneurysm and aortic neck on follow-up after endovascular repair with suprarenal fixation

INFLUENCE OF PROXIMAL FIXATION ON ANEURYSM NECK EVOLUTION AFTER ENDOVASCULAR TREATMENT OF INFRARENAL ANEURYSMS

OBJECTIVE

We analyzed the long-term influence of fixation systems on proximal aortic neck (PAN) evolution by comparing two late-generation endoprostheses, Endurant (Medtronic Vascular, Minneapolis, Minn) with suprarenal fixation (SRF) and Excluder (W.L Gore & Associates, Flagstaff, Ariz) with infrarenal fixation (IRF).

METHODS

Our retrospective observational study included consecutive patients undergoing EVAR for aorto-iliac aneurysms (2011-2020). Primary end points: neck enlargement and freedom from significative PAN enlargement (5 mm). Secondary end points: neck-related reintervention, endoleaks and graft migration. Results were reported following the Society of Vascular Surgery reporting standards.

RESULTS

139 patients were included (97 in SRF group and 42 in IRF group). A difference in growth at 10 mm caudal to lowest renal artery at 2 years follow-up was found (mean growth of 1.92 ± 3.38 mm in SRF and 0.16 ± 6.86 mm in IRF; p <.001). A tendency to a major growth in SRF at 4 years follow-up at the lowest renal artery (1.27 ± 3.36 mm vs 0.63 ± 2.2 mm; p = .06), 5 mm distal to lowest renal artery (2.17 ± 3.52 mm vs 0.94 ± 2.76 mm; p =.001) and 10 mm distal to lowest renal artery (2.65 ± 3.86 mm vs 1.12 ± 1.5 mm; p <.001) was shown. Freedom from PAN enlargement was 96.65% and 88.20% in SRF and 100% and 94.4% in IRF at 2 and 4 years follow up respectively (log rank .041). A greater incidence of type II endoleaks in IRF was observed (40.48% vs 15.46%;p =.001). Oversizing > 15% showed to be a risk factor of PAN enlargement (OR 6.85; 95% IC 1.67 - 28.4; p =.007).

CONCLUSIONS

A small but significative percentage of patients after EVAR show a progressive PAN enlargement, being significatively greater in SRF, without increasing neck related complications four years after graft deployment.

Predictive Factors for Iliac Limb Occlusions After Endovascular Abdominal Aneurysm Repair: Determined from Aortoiliac Anatomy, Endovascular Procedures, and Aneurysmal Remodeling

Purpose

Iliac limb occlusion (ILO) is a serious complication of endovascular abdominal aneurysm repair (EVAR). This study aimed to identify predictive factors for ILO derived from aortoiliac morphology, endovascular procedure-related parameters, and aneurysmal remodeling characteristics.

Patients and Methods

Patient demographics, pre-EVAR anatomical characteristics of the aneurysm, endovascular procedure details, and post-EVAR aneurysmal remodeling outcomes were analyzed and compared using univariate analysis. Statistically significant factors were subsequently subjected to Cox regression and Kaplan-Meier analyses.

Results

Between January 2013 and April 2022, 66 patients were included in this study. Fourteen patients presented with ILO and were compared with 52 control patients with patent endograft limb over at least 1-year of follow-up. The tortuosity indices of the common iliac artery (CIA) and endograft iliac limb to vessel oversizing were significantly larger in the ILO group than in the patent endograft limb group. The CIA index of tortuosity ≥1.08, and endograft iliac limb to vessel oversizing ≥18.8% were independent predictors for ILO. During the follow-up of all patients, the proximal aortic neck and CIA diameters increased, aneurysm sac diameter decreased, and aortic neck and aortic length increased. The aortoiliac length increased over time in patients with patent endograft limb but not in patients with ILO. A change in the lowest renal artery-left iliac bifurcation distance ≦0.07 mm increased the risk of ILO.

Conclusion

ILO is predisposed to occur when the CIA index of tortuosity ≥1.08 and endograft iliac limb to vessel oversizing ≥18.8% are present. Significant aortoiliac remodeling, including proximal aortic neck dilatation, neck straightening, aneurysmal sac regression, iliac artery enlargement, and aortic lengthening, occurs after EVAR. Aortoiliac elongation was observed in patients with patent endograft limb, but not in patients with ILO. ILO was associated with a change in the lowest renal artery-left iliac bifurcation from the postoperative measurements ≦ 0.07 mm.

Early outcomes of the Conformable endograft in severe neck angulation from the Triveneto Conformable Registry

OBJECTIVE

The study reports retrospective evaluation of early outcomes from a multicentric experience with the Excluder conformable endograft with active control system (CEXC Device) in the treatment of abdominal aortic aneurysms. Its design allows more flexibility, given by proximal unconnected stent rows and a bending wire within the delivery catheter enables control of proximal angulation. This study specifically focuses on the severe neck angulation (SNA) subgroup (≥60°).

METHODS

All patients treated with CEXC Device in nine vascular surgery centers of Triveneto area (Northeast Italy) between January 2019 and July 2022 were enrolled prospectively and analyzed retrospectively. Demographic and aortic anatomical characteristics were evaluated. Endovascular aneurysm repair in SNA were selected for analysis. Major investigated outcomes were technical success, endoleaks, morbidity, mortality, and reinterventions at 30 days and during follow-up. Endograft migration and postoperative aortic neck angulation changes were also analyzed.

RESULTS

A total of 129 patients were enrolled. An infrarenal angle of ≥60° was observed in 56 patients (43%) (SNA group) and their data analyzed. The mean patient age was 78.9 ± 5.9 years and median abdominal aortic aneurysm diameter 59 mm (range, 45-94 mm). Median aortic infrarenal neck length, angulation and diameter were 22 mm (range, 13-58 mm), 77° (range, 60°-150°), and 22.0 ± 3.5 mm respectively. Analysis revealed a technical success rate of 100% and perioperative major complication rate of 1.7%. Intraoperative and perioperative morbidity and mortality rates were 3.5% (one buttock claudication and one inguinal surgical cutdown) and 0%, respectively. No perioperative type I endoleaks were observed. The median follow-up was 13 months (range, 1-40 months). Five patients died during follow-up from aneurysm-unrelated causes. Two reinterventions occurred (3.5%): one conversion for a type IA endoleak and one sac embolization for a type II endoleak. Aneurysm sac shrinkage was observed in 15 patients (26%) and aneurysm stability in 35 patients (62%), respectively. Estimated freedom from reinterventions at 24 months was 92%. Aortic neck median postoperative angulation was 75° (range, 45°-139°).

CONCLUSIONS

The Triveneto Conformable Registry shows good early results of the CEXC device in severely angulated aortic infrarenal necks. These data need confirmation on longer follow-up and a wider cohort of patients to further increase endovascular aneurysm repair eligibility in SNA.

In vitro evaluation of the optimal degree of oversizing of thoracic endografts in prosthetic landing areas: a pilot study

Objective

The optimal degree of proximal thoracic endograft oversizing when aiming for durable sealing in prosthetic grafts is unknown. The aim of the present study was to create an in vitro model for testing different oversized thoracic endografts in a reproducible and standardized manner and, subsequently, determine the optimal oversizing range when planning procedures with a proximal landing in prosthetic zones in the descending thoracic aorta or aortic arch.

Methods

An in vitro model consisting of a fixed 24-mm polyethylene terephthalate (Dacron; DuPont) graft sutured proximally and distally to two specifically designed 40-mm rings, with four force sensing resistors attached at four equally distant positions and a USB camera attached proximally for photographic and video documentation was used for deployment of Zenith TX2 (Cook Medical Inc) dissection platform endografts with diameters between 24 and 36 mm. After deployment, ballooning with a 32-mm compliant balloon was performed to simulate real-life conditions. The assessment of oversizing included visual inspection, calculation of the valley areas created between the prosthetic wall and the stent graft fabric, distance between the stent graft peaks, the radial force exerted by the proximal sealing stent, and the pull-out force necessary for endograft extraction.

Results

A total of 70 endografts were deployed with the oversizing ranging from 0% to 50%: 10 × 24 mm, 10 × 26 mm, 10 × 28 mm, 10 × 30 mm, 10 × 32 mm, 10 × 34 mm, and 10 × 36 mm. Two cases of infolding occurred with 50% oversizing. The valley areas increased from 8.79 ± 0.23 mm² with 16.7% oversizing to 14.26 ± 0.45 mm² with 50% oversizing (P < .001). A significant difference was found in the pull-out force required for endografts with <10% oversizing vs ≥10% oversizing (P < .001). The difference reached a plateau at ∼4 N with oversizing of >15%. The mean radial force of the proximal sealing stent was greater after remodeling with a compliant balloon (0.55 ± 0.02 N vs 0.60 ± 0.02 N after ballooning; P < .001). However, greater oversizing did not lead to an increase in the radial force exerted by the proximal sealing stent.

Conclusions

The findings from the present study offer additional insight into the mechanics of oversized stent grafts in surgical grafts. In endografts with the Zenith stent design (TX2), oversizing of <16.7% resulted in reduced resistance to displacement forces, and oversizing of >50% was associated with major infolding in 20% of cases. Long-term in vitro and in vivo testing is required to understand how these mechanical properties affect the clinical outcomes of oversizing.

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.

Aortic Visceral Segment Instability is evident following Thoracic Endovascular Aortic Repair for Acute and Subacute Type B Aortic Dissection

BACKGROUND

Anatomic remodeling within the thoracic aorta following thoracic endovascular aortic repair (TEVAR) for type B aortic dissections (TBAD) has been well documented, but less is known about the response of the untreated visceral aorta. This study aims to investigate visceral aortic behavior following TEVAR for acute or subacute TBAD and identify associations with clinical outcomes.

METHODS

A multi-center retrospective review was performed of all imaging for all patients treated with TEVAR for acute (0-14 days) and subacute (14-90 days) non-traumatic TBAD between 2006-2020. Cohort was inclusive of uncomplicated, high-risk, and complicated (defined per SVS reporting guidelines) dissections. Centerline aortic measurements of the true and false lumen and total aortic diameter (TAD) were taken at standardized locations relative to aortic anatomy within each aortic zone (zones defined by SVS reporting guidelines). Diameter changes over time were evaluated using repeated measures mixed effects linear growth modeling. Visceral segment instability (VSI) was defined as any growth in TAD ≥ 5mm within aortic zones 5 through 9.

RESULTS

A total of 82 patients were identified. Median length of imaging follow-up was 2.1 years (IQR 3.9 years), with 15% of the cohort having follow-up longer than 5 years. VSI was present in 55% of the cohort, with an average maximal increase in TAD of 10.4±6.3 mm over a median follow-up of 2.1 years (IQR 3.9 years). Roughly a third of the cohort experienced rapid VSI (growth ≥5mm in first year), and 4.8% of the cohort developed a large para-visceral aneurysm aortic (TAD≥5cm) secondary to VSI. Linear growth modeling identified significant predictable growth in TAD across all visceral zones. Zones 7 had the highest rate of TAD dilation, with a fixed effect estimated rate of 1.3 mm per year (95%-CI 0.23-2.1, p=0.022). The preoperative factor most strongly associated with VSI was ≥6 cumulative number of zones dissected (OR 6.4, 95% OR 1.07-8.6, p=0.041). Odds for aortic reintervention were significantly increased in cases where VSI led to development of a para-visceral aortic aneurysm ≥5cm development (OR 3.7, 95%-CI 1.1-13, p=0.038).

CONCLUSION

VSI was identified in the majority of patients treated with TEVAR for management of acute and subacute TBAD. Preoperative anatomic features such as extent of dissection, rather than procedural details of graft coverage, may play a more significant role in VSI occurrence. Importantly, significant TAD growth occurred in all visceral segments. These results highlight the importance of lifelong surveillance following TEVAR, and identify a subset of patients that may be at increased risk for re-intervention.

Fenestrated EVAR Promotes Positive Infrarenal Neck Remodeling and Greater Sac Shrinkage compared to EVAR

OBJECTIVES

Endovascular aortic aneurysm repair (EVAR) has become the standard of care treatment for abdominal aortic aneurysms (AAA) in the modern era. While numerous devices exist for standard infrarenal AAA repair, fenestrated endovascular aneurysm repair (fEVAR) offers a minimally invasive alternative to traditional open repair in patients with short infrarenal necks. Over time, aortic neck dilation can occur leading to loss of proximal seal, endoleaks, and AAA sac growth. This study analyzes aortic remodeling following EVAR versus fEVAR and further evaluates whether fEVAR confers a benefit in terms of sac shrinkage.

METHODS

A retrospective review of prospectively collected data on 120 patients undergoing EVAR was performed: 30 patients were treated with fEVAR (Cook Zenith© Fenestrated) and 90 patients were treated with EVAR devices (30 with each Medtronic Endurant ©, Gore Excluder ©, and Cook Zenith ©). Demographic data were recorded, and anatomic measurements were taken for each patient pre-operatively, 30 days post-operatively, and at the longest point of follow-up using three-dimensional reconstruction software.

RESULTS

There were no significant differences in demographics data between the 4 groups. fEVAR was used more often in aortas with large necks and irregular morphology (p= 0.004). At the time of longest follow up, the suprarenal aorta encompassing 5, 10, and 15mm above the lowest renal artery (ALRA) dilated the most for fEVAR versus all EVAR groups. Despite this, the infrarenal segment tended to increase by the least, or even regress, for fEVAR compared to all EVAR groups, and was associated with the overall greatest proportion of sac shrinkage for the fEVAR group compared to Medtronic, Gore, and Cook devices, respectively (-13.90% vs. -5.75% vs. -2.31% vs. -4.68%, p=0.025).

CONCLUSIONS

Compared to EVAR, patients treated with fEVAR had greater suprarenal dilation over time, consistent with an overall greater burden of disease in the proximal native aorta. However, the infrarenal segment dilated significantly less over time in the fEVAR group compared to all EVAR groups, suggesting that fEVAR may stabilize the infrarenal neck, promoting positive sac remodeling, as evidenced by the greatest degree of decrease in largest AAA diameter in the fEVAR group.

A meta-analysis of safety and efficacy of endovascular aneurysm repair in aneurysm patients with severe angulated infrarenal neck

Objectives

A growing number of abdominal aortic aneurysms with severe angulated neck anatomy is treated by endovascular means. However, contradictory early and late outcomes have been reported. Our review and outcome analysis attempted to evaluate the available literature and provide clinicians with a base for clinical implementation and future research.

Materials and methods

A systematic review of the literature was undertaken to identify the outcomes of endovascular aneurysm repair in patients with severe infrarenal neck angulation (SNA ≥ 60°) vs non-severe neck angulation (NSNA). Outcome measures included perioperative complications, type 1a endoleak, neck-related secondary procedures, stent graft migration, aneurysm rupture, increase (>5mm) in sac diameter, all-cause and aneurysm-related mortality (PROSPERO Nr.: CRD42021233253).

Results

Six observational studies reporting on 5981 patients (1457 with SNA and 4524 with NSNA) with a weighted mean follow-up period of 1.8 years were included. EVAR in SNA compared with NSNA was associated with a higher rate of type 1a endoleak at 30 days (4.0% vs 1.8%; p< 0.00001), at 1 year (2.8% vs 1.9%; p<0.03), at 2 years (4.9% vs 2.1%; p< 0.0002), at 3 years (5.6% vs 2.6%; p< 0.0001). The rate of neck-related secondary procedures was significantly higher at 1 year (6.6% vs 3.9%; p<0.05) and at 3 years (13.1% vs 9%; p<0.05). Graft migration, aneurysm sack increase, aneurysm rupture and all-cause mortality were not statistically different at mid-term.

Conclusions

The use of EVAR in severely angulated infrarenal aortic necks is associated with a high rate of early and mid-term complications. However, aortic related and all-causes mortality are not higher compared to patients with NSNA. Therefore, EVAR should be cautiously used in patients with SNA.

Endograft apposition and infrarenal neck enlargement after endovascular aortic aneurysm repair

BACKGROUND

Sufficient apposition and oversizing of the endograft in the aortic neck are both essential for durable endovascular aneurysm repair (EVAR). These measures are however not regularly stated on post-EVAR computed tomography angiography (CTA) scan reports. In this study endograft apposition and neck enlargement (NE) after EVAR with an Endurant II(s) endograft were analyzed and associated with supra- and infrarenal aortic neck morphology.

METHODS

In 97 consecutive elective patients, the aortic neck morphology was measured on the pre-EVAR CTA scan on a 3mensio vascular workstation. The distance between the lowest renal artery and the proximal edge of the fabric (shortest fabric distance, SFD), and the shortest length of circumferential apposition between endograft and aortic wall (shortest apposition length, SAL) was determined on the early post-EVAR CTA scan. NE, defined as the aortic diameter change between pre- and post-EVAR CTA scan, was determined at eight levels: +40, +30, +20, +15, +10, 0, -5 and -10 mm relative to the lowest renal artery baseline. The aortic neck diameter and preoperative oversizing were correlated to NE with the Pearson correlation coefficient. The effective post-EVAR endograft oversizing is calculated from the nominal endograft diameter and the post-EVAR neck diameter where the endograft is circumferentially apposed.

RESULTS

The median time (interquartile range, IQR) between the EVAR procedure and the pre- and post-EVAR CTA scan was 40 (25, 71) days and 36 (30, 46) days, respectively. The Endurant II(s) endograft was deployed with a median (IQR) SFD of 1.0 (0.0, 3.0) mm. The SAL was <10 mm in 9% of patients and significantly influenced by the pre-EVAR aortic neck length (p=0.001), hostile neck shape (p=0.017), and maximum curvature at the suprarenal aorta (p=0.039). The median (interquartile range) SAL was 21.0 (15.0, 27.0) mm with a median (IQR) pre-EVAR infrarenal neck length of 23.5 (13.0, 34.8) mm. The median (IQR) difference between the SAL and neck length was -5.0 (-12.0, 2.8) mm. Significant (p<.001) NE of 1.7 (0.9, 2.5) mm was observed 5 mm below the renal artery baseline, which resulted in an effective post-EVAR endograft oversizing <10% in 43% of the patients. No correlation was found between NE and aortic neck diameter or preoperative oversizing.

CONCLUSIONS

Circumferential apposition between an endograft and the infrarenal aortic neck, SAL, and NE can be derived from standard postoperative CT scans. These variables provide essential information about the post-procedural endograft and aortic neck morphology regardless of the preoperative measurements. Patients with SAL <10 mm or effective oversizing <10% due to NE may benefit from intensified follow-up, but clinical consequences of SAL and NE should be evaluated in future longitudinal studies with longer term follow-up.

Prognostic Role of Severe Infrarenal Aortic Neck Angulation in Endovascular Aneurysm Repair

OBJECTIVE

To investigate whether patients with severe infrarenal aortic neck angulation have worse outcomes than those without severe angulation after endovascular aneurysm repair (EVAR).

DATA SOURCES

The HDAS (Healthcare Database Advanced Search) interface developed by NICE (National Institute for Health and Care Excellence) was used to search electronic bibliographic databases.

REVIEW METHODS

Studies comparing outcomes of standard EVAR in patients with and without severe neck angulation were considered. Pooled outcome estimates were calculated using the odds ratio (OR) or hazard ratio (HR) and 95% confidence interval (CI), using the Mantel-Haenszel or inverse variance method, as appropriate. Random effects models of meta-analysis were applied. The GRADE (Grading of Recommendation, Assessment, Development, and Evaluation) methodology was used to assess the certainty of evidence.

RESULTS

Ten studies reporting a total of 7 371 patients (1 576 with severe neck angulation and 5 795 without) were included. The studies reported medium term follow up. No statistically significant difference was found for the primary outcomes (overall mortality: HR 1.27, 95% CI 0.88 - 1.85, low certainty; aneurysm related mortality: HR 1.07, 95% CI 0.80 - 1.44, moderate certainty; aneurysm rupture: HR 1.41, 95% CI 0.66 - 2.99, low certainty). The hazard of type Ia endoleak (HR 1.86, 95% CI 1.32 - 2.61) and re-intervention was higher in patient with severe angulation (HR 1.24, 95% CI 1.01 - 1.54), but there was no significant difference in the odds of adjunctive procedures (OR 1.23, 95% CI 0.48 - 3.11), or the hazard of sac expansion (HR 0.83, 95% CI 0.44 - 1.55) or stent migration (HR 1.22, 95% CI 0.78 - 1.92). Meta-analysis of studies that conducted multiple Cox regression analysis showed no significant difference for any of the primary outcomes.

CONCLUSION

Severe neck angulation may not be a poor prognostic indicator for overall/aneurysm related mortality and rupture in the medium term after EVAR but may increase the risk of late type 1 endoleaks and re-intervention; therefore, patients require close surveillance.

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.

Significant aortic neck dilation occurs after repair of juxtarenal aneurysms with fenestrated endovascular aneurysm repair

OBJECTIVE

Aortic neck dilation is a reported mode of failure and can be associated with aneurysm sac expansion after standard endovascular abdominal aortic aneurysm repair (EVAR). Fenestrated EVAR (FEVAR) of the juxtarenal segment increases the seal zone length and is often used to treat this disease progression. However, the frequency and risk factors for neck dilation after FEVAR is unknown.

METHODS

We evaluated 124 consecutive FEVARs performed under an investigational device exemption clinical trial for juxtarenal aneurysms (ClinicalTrials.gov identifier, NCT01538056). The aortic diameter at the level of the superior mesenteric artery (SMA; highest fenestration) and lowest renal artery (lowest fenestration) was assessed from computed tomography angiography preoperatively, at 30 days, and annually thereafter. A subgroup analysis was performed to assess aortic neck dilation by the graft type used, degree of oversizing, infrarenal neck length, effective seal zone length, and aortic diameter at the level of the lowest and highest fenestration. Multivariable analysis was then performed to evaluate for predictors of aortic neck dilation.

RESULTS

Of the 124 patients, 56 had complete anatomic detail and follow-up data available for ≥3 years. Those without preoperative or follow-up data available were excluded. The aortic diameter had increased significantly by 3 years at the level of both the SMA (2.4 mm; P < .01) and the lowest renal artery (3.2 mm; P < .01). When those with and without aortic dilation (>3 mm) were compared, only oversizing differed at the level of the SMA (14% vs 19%; P < .01). At the level of the lowest renal artery, the graft diameter differed (30 mm vs 28 mm; P = .02). However, after adjusted analysis, these differences were not significant. Finally, a subgroup analysis was performed to evaluate aortic dilation over time stratified by anatomic factors and should that aortic dilation occurred across differing aneurysm diameters, percentage of oversizing, graft types, and seal zone lengths.

CONCLUSIONS

Aortic neck dilation in the visceral segment can occur after endovascular repair of juxtarenal aneurysms using FEVAR. Further research is warranted to determine how these changes might affect the long-term outcomes.

Evolving Concepts, Management, and Treatment of Type 1 Endoleaks after Endovascular Aneurysm Repair

Over the past 20 years, there has been tremendous progress in endovascular aneurysm repair techniques and devices. The application of new third- and fourth-generation devices (from 2003 onward) has led to changes in the incidence and management of endoleaks. This comprehensive review aims to outline the most recent concepts with respect to pathophysiology/risk factors and management of Type 1 endoleaks.

Risk Factors for Early and Late Type Ib Endoleak Following Endovascular Abdominal Aortic Aneurysm Repair

OBJECTIVES

A type Ib endoleak (T1bEL) is a postoperative complication that usually requires additional interventions following endovascular aortic aneurysm repair. Previous studies have focused on iliac artery tortuosity or common iliac artery (CIA) diameter. However, we investigated the various risk factors for early and late T1bELs more comprehensively.

METHODS

This retrospective case-control study of a prospectively maintained database compared anatomical, demographic and technical factors between patients with early or late T1bELs and a control group. Early T1bEL was defined as a T1bEL occurring within 6 months of endovascular aneurysm repair (EVAR), while late T1bEL was defined as a T1bEL, initially identified more than 6 months after EVAR. Anatomical values including neck diameter, length, and angle; maximum sac diameter and length; CIA length, diameter, and tortuosity; and distal sealing length were measured and included in the analysis. We performed uni- and multivariable analyses using logistic regression and Cox proportional hazard models.

RESULTS

This study included 635 iliac limbs of 383 patients. Overall, T1bELs occurred in 22 iliac limbs during the follow-up period (22/635, 3.5%). Among them, the early and late T1bEL groups each included 11 limbs. The median follow-up duration of the 383 patients was 23 (8-58) months, and in the early T1bEL and early control groups, the durations were 15 (9-35) and 29 (15-60) months, respectively (P = 0.01). The median overall follow-up durations in the late T1bEL and late control groups were 87 (76-102) and 62 (48-80) months, respectively (P = 0.01). The median follow-up duration until the occurrence of late T1bEL was 44 (32-82) months, which was shorter than that of the late control group (P = 0.03). No significant differences in sex, age, or brand of stent-graft were observed between the T1bEL and control groups. In the multivariable analysis, patients in the early T1bEL group had significantly more tortuous and short CIAs, and short distal sealing lengths (P = 0.02, P = 0.04, P = 0.03, respectively), and the late T1bEL group had significantly larger maximum aortic aneurysm sac diameters, short CIAs and short distal sealing lengths (P < 0.001, P = 0.02, P = 0.002, respectively). The suspected mechanisms of the T1bELs were CIA dilatation with or without sac expansion and aggravation of sac angulation. Except for one patient with aortic dissection, T1bELs were treated with iliac limb extensions.

CONCLUSIONS

The various mechanisms of T1bELs differed depending on the time of onset from the procedure. An extensive sealing length may be protective against T1bEL, especially when the size of the aortic aneurysm sac is large or when the CIA has risky features, including large diameter or short length. Careful preoperative consideration of aortic aneurysm size and CIA length and tortuosity is essential, and patients with risky features should undergo strict postoperative surveillance.

Thoracic aortic remodeling with endografting after a decade of thoracic endovascular aortic repair experience

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) results have been studied in short-term time frames. This study aimed to evaluate midterm and long-term outcomes of TEVAR, emphasizing postoperative aortic remodeling and need for reintervention.

METHODS

This is an institutional retrospective review of TEVAR for isolated descending thoracic aortic aneurysms. Data were collected from 2004 to 2018. Primary outcomes studied included aneurysm sac remodeling, freedom from reintervention, and all-cause mortality. Other outcomes studied include endoleak rates, neurologic complication rates, and any overall postoperative complication rates.

RESULTS

During the study period, 219 patients underwent TEVAR for descending thoracic aortic aneurysms. The median effect of TEVAR on sac diameter was a 0.7-cm decrease in size (interquartile range, -1.4 to 0.0 cm). During the study period, 80% (n = 147) of patients experienced aneurysm sac regression or stability. Perioperative neurologic complications occurred in 16% (n = 34) of patients. Significant predictors of sac growth were endoleak (odds ratio [OR], 65; P < .001), preoperative carotid-subclavian bypass (OR, 8; P = .003), and graft oversizing <20% (OR, 15; P = .046). Every 1-mm increase in aortic diameter at the proximal TEVAR landing zone led to an increased odds of endoleak (OR, 2; P = .049). Access complications (OR, 8) and subclavian artery coverage (OR, 6) significantly increased the odds of reintervention, whereas every percentage of graft oversizing protected against reintervention (OR, 0.005). Life-table analysis revealed an overall survival of 78% (71%-83%) at median follow-up. At 3 years, survival was 88% (80%-93%) for those with aneurysm sac stability or regression, whereas it was 70% (49%-84%) for those with aneurysm sac growth (P = .0402). Cox proportional hazards model showed that the only protective factor for mortality was percentage oversizing, with every 1% of oversizing having a hazard ratio (HR) of <.001 (P = .032). This was counterbalanced by the fact that patients with graft oversizing >30% had an increased odds of mortality with HR >10 (P = .049). Other significant factors that increased the odds of mortality included endoleak (HR, 3.6; P = .033), diabetes (HR, 4.1; P = .048), age (every 1-year increase in age; HR, 1.2; P = .002), year of surgery (every year subsequent to 2004; HR, 1.3; P = .012), and peripheral artery disease (HR, 5.2; P = .041).

CONCLUSIONS

The majority of patients (80%) experience sac stability or regression after TEVAR, which offers a clear survival advantage. Endoleaks are predictive of sac growth, conferring increased mortality. Rigorous surveillance is necessary to prevent future aortic events through reintervention.

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.

Evolving concepts and management of endoleaks after endovascular aneurysm repair: where do we stand in 2019?

In recent years, there has been tremendous progress in endovascular aneurysm repair (EVAR) techniques and devices. This process has seen a change in incidence, risk factors, and treatment of endoleaks as well as in follow-up protocols after EVAR. In particular, recent literature has highlighted new concepts in the evaluation and prevention/treatment of type I and II endoleak after standard EVAR. There is also recent evidence regarding new imaging protocols for follow-up after EVAR, which include magnetic resonance imaging and contrast-enhanced ultrasound. This comprehensive review aims to outline the most recent concepts on imaging follow-up, pathophysiology/risk factors, and management of endoleaks.

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.

Changes in Apposition of Endograft Limbs in the Iliac Arteries After Endovascular Aneurysm Repair: Determination With New Computed Tomography-Applied Software

Purpose: To validate new computed tomography (CT)-applied software used to determine endograft limb position and apposition after endovascular aneurysm repair (EVAR). Materials and Methods: Twelve EVAR patients (mean age 81±6 years; 10 men) with distal stent-graft extensions for 15 (3 bilateral) type Ib endoleaks during follow-up were selected based on the availability of the following CT studies: pre-EVAR, 1 month, and the penultimate scan prior to the scan disclosing the type Ib endoleak. Twelve patients (mean age 82±7 years; 11 men) without endoleak and a similar interval between the primary EVAR procedure and the penultimate CT scan of the endoleak group were selected as controls using measurements from both endograft limbs (n=21, 3 excluded). Prototype Vascular Imaging Analysis software was adapted to calculate 6 parameters for the distal apposition zone: fabric distance, shortest apposition length, endograft diameter, iliac seal surface (ISS), iliac endograft apposition surface (IEAS), and percentage of iliac surface coverage (IEAS/ISS × 100). Measurements were performed on the preoperative, first postoperative, and penultimate/matched follow-up CT scans. Interobserver variability was assessed with the intraclass correlation coefficient (ICC). Continuous data are presented as the median [interquartile range (IQR) Q1, Q3]. Results: CTA follow-up was not significantly different between the endoleak and control groups [30 months (IQR 18, 58) vs 36 months (IQR 21, 59), p=0.843]. Interobserver agreement was good to excellent for all parameters (ICC 0.879-0.985). Preoperative anatomy and endograft dimensions on the first follow-up CTA scan did not differ significantly between the groups. When the penultimate CTA scan was compared with the first postoperative CT scan, endograft dimensions had significantly changed in the endoleak group; importantly, apposition was significantly decreased, and fabric distance was significantly increased, indicating limb retraction. Differences in changes in endograft dimensions were significant between the groups. Conclusion: New CT-applied software was introduced to visualize apposition and position changes of endograft limbs during follow-up. The software demonstrated good-to-excellent interobserver agreement and enabled accurate analysis of post-EVAR endograft dimensions. Significant changes in apposition and position were observed with the software on the penultimate CT scan prior to diagnosis of type Ib endoleak.

Suprarenal Aortic Remodeling after Endovascular Aortic Aneurysm Repair among Three Endografts with Different Types of Proximal Fixation System

BACKGROUND

Remodeling of suprarenal aorta after endovascular aortic aneurysm repair (EVAR) in relation to different endograft designs has not been thoroughly investigated. The aim of this study is to assess the anatomical configuration of the suprarenal aorta after using endografts with different proximal fixation during the first post-EVAR year.

METHODS

A retrospective study including EVAR patients using 3 types of endografts with different proximal fixation systems according to Instructions for Use was undertaken (50: Ovation, Endologix, Irvin, CA; 25: Endurant IIs, Medtronic, Santa Rosa, CA; 25: Excluder C3, W. L. Gore & Associates, Flagstaff, AZ). Comorbidities were recorded. Anatomic variables of the supra-aortic anatomy, abdominal aortic aneurysm (AAA) maximum diameter, and neck angulation were analyzed. Computed tomography angiography was obtained preoperatively at 1 and 12 months post-EVAR, while a duplex scan was undertaken at 6 months.

RESULTS

Comorbidities were not different across the 3 groups. Presence and amount of neck calcification (P = 0.139) and thrombus (P = 0.116) was similar among groups. Maximum aortic diameter showed significant reduction from preoperative measurements to 12-month postoperative ones, for all groups. (Ovation: 56.5 to 53 mm, P < 0.001; Endurant: 57 to 51 mm, P < 0.001; Excluder: 55 to 50 mm, P < 0.001). Suprarenal angulation was decreased significantly in the Ovation (P < 0.001) and Excluder groups (P = 0.05), while the infrarenal angulation was decreased in all groups. Among endografts, the decrease in AAA maximum diameter was similar (P = 0.99), while the suprarenal aortic diameter was significantly increased in Ovation patients in comparison to the other 2 endografts at the level of 5 mm (P = 0.02) and 25 mm (P = 0.01). Suprarenal angulation reduction was similar (P = 0.7), while infrarenal angulation was significantly more decreased in Ovation endograft than the other 2 systems (P < 0.001).

CONCLUSIONS

Proximal endograft configuration appears to have different impact on supra-aortic anatomy. Longer follow-up is needed to clarify future remodeling and clinical impact of these observations.

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.

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.