Results of the endovascular abdominal aortic aneurysm repair using the Anaconda aortic endograft

Endograft Anaconda in Endovascular Aneurysm Repair: A Systematic Review of Literature and Meta-Analysis

BACKGOUND

The number of endovascular abdominal aortic aneurysm repairs (EVARs) has surpassed the number of open surgical repair of AAAs worldwide with a great variety of endografts being available. The aim of this study is to conduct a systematic review of the literature and meta-analysis of studies reporting patients with infrarenal abdominal aortic aneurysm (AAA) subjected to EVAR with the Anaconda endograft.

METHODS

We performed a systematic review of multiple electronic databases for studies including patients with infrarenal AAA who were subjected to elective EVAR with Anaconda endograft exclusively. We conducted a proportional meta-analysis cumulating the results of the included studies. The endpoints were first month overall mortality, first and second-year survival after EVAR, AAA-related deaths, incidence of endoleaks, endograft migration, endograft occlusion, open conversion, and primary and secondary technical success. The mean value for each separate studied factor was calculated, and the respective percentage or incidence was extracted so that it can be compared to endograft outcome studies in the literature. We assessed the methodologic quality of studies by using the Briggs Institute critical appraisal tool.

RESULTS

Seven observational studies were found including 954 patients (males 91.9%, mean age 73.38 ± 6.97 years). The mean transverse diameter of AAAs was 56.83 ± 9.97 mm. The mean proximal aortic neck diameter and length were 23.06 ± 3.33 mm and 24.14 ± 12.16 mm, respectively. Increased aortic neck calcification and aortic neck thrombus were present in 12.5% of patients. The 30-day overall mortality post-EVAR was 1.3%, 1 and 2-year survival rates were 95.9% and 91.4%, respectively. The mean follow-up period in the studies was 46.59 ± 15.5 months. AAA-related mortality was 1.3%. Primary technical success was 97.9% and secondary success was 99.3%. Open conversion was required in 3.4% of all patients (0.6% during the primary operation [Prim. Op]). The most common endoleak was type II, reported in 17.4% of all patients. Early type Ia endoleak was reported in 1.5% of patients and late type Ia in 1.7%. Overall, 2 endoleaks type III and 1 type IV were reported. Endograft migration occurred in 1.7% of patients. Main body and/or one/both iliac legs thrombotic occlusion was found totally in 7.6% of patients (5 main body occlusions and 64 iliac leg occlusions).

CONCLUSIONS

The use of Anaconda endograft in electively treated patients with infrarenal AAAs presented good results with high technical success and low postoperative and mid-term complications, except for an increased incidence of stent-graft thrombosis, which seems to be the "Achilles heel" of the device.

Ultrasound Particle Image Velocimetry to Investigate Potential Hemodynamic Causes of Limb Thrombosis After Endovascular Aneurysm Repair With the Anaconda Device

PURPOSE

To identify potential hemodynamic predictors for limb thrombosis (LT) following endovascular aneurysm repair with the Anaconda endograft in a patient-specific phantom.

MATERIALS AND METHODS

A thin-walled flow phantom, based on a patient's aortic anatomy and treated with an Anaconda endograft, that presented with a left-sided LT was fabricated. Contrast-enhanced ultrasound particle image velocimetry was performed to quantify time-resolved velocity fields. Measurements were performed in the same phantom with and without the Anaconda endograft, to investigate the impact of the endograft on the local flow fields. Hemodynamic parameters, namely vector complexity (VC) and residence time (RT), were calculated for both iliac arteries.

RESULTS

In both limbs, the vector fields were mostly unidirectional during the peak systolic and end-systolic velocity phases before and after endograft placement. Local vortical structures and complex flow fields were observed at the diastolic and transitional flow phases. The average VC was higher (0.11) in the phantom with endograft, compared to the phantom without endograft (0.05). Notably, in both left and right iliac arteries, the anterior wall regions corresponded to a 2- and 4-fold increase in VC in the phantom with endograft, respectively. RT simulations showed values of 1.3 to 6 seconds in the phantom without endograft. A higher RT (up to 25 seconds) was observed in the phantom with endograft, in which the left iliac artery, with LT in follow-up, showed 2 fluid stasis regions.

CONCLUSION

This in vitro study shows that unfavorable hemodynamics were present mostly in the limb that thrombosed during follow-up, with the highest VC and longest RT. These parameters might be valuable in predicting the occurrence of LT in the future.

CLINICAL IMPACT

This in-vitro study aimed to identify potential hemodynamic predictors for limb thrombosis following EVAR using ultrasound particle image velocimetry (echoPIV) technique. It was shown that unfavorable hemodynamic norms were present mostly in the thrombosed limb. Owing to the in-vivo feasibility of the echoPIV, future efforts should focus on the evaluation of these hemodynamic norms in clinical trials. Thereafter, using echoPIV as a bedside technique in hospitals becomes more promising. Performing echoPIV in pre-op phase may provide valuable insights for surgeons to enhance treatment planning. EchoPIV is also applicable for follow-up sessions to evaluate treatment progress and avoid/predict complications.

Geometrical Changes of the Aorta as Predictors for Thromboembolic Events After EVAR With the Anaconda Stent-Graft

PURPOSE

Thromboembolic events (TE), including limb graft occlusion (LGO) and distal limb embolization (DLE), are common complications after endovascular aneurysm repair (EVAR). The aim of this study was to find predictors for TE in patients treated with the Anaconda stent-graft for infrarenal aneurysms.

MATERIALS AND METHODS

Geometrical and anatomical variables were retrospectively analyzed in a consecutive Anaconda cohort. Pre- and postoperative CT scans were used to derive geometrical parameters length, curvature, torsion, and tortuosity index (TI) from the center lumen lines (CLLs). Limb characteristics, pre-to-post EVAR and mid-term-follow-up changes in the parameters were evaluated for their predictive value for TE.

RESULTS

Eighty-four patients (mean age 74±8.3 years, 74 men) were enrolled. The risk of TE was lowered with pre-to-post implant decreasing TI (steps of 0.05: OR: 1.30, 95% CI: 1.01-1.66, p=0.04), pre-to-post implant decreasing mean curvature (OR: 1.08, 95% CI: 1.01-1.16, p=0.03), and a larger degree of circumferential common iliac artery (CIA) calcification (OR: 0.98, 95% CI: 0.97-1.00, p=0.03). The only LGO predictor was the caudal relocation of maximal curvature after EVAR (OR: 1.01, 95% CI: 1.00-1.01, p=0.04). Preventors of DLE were CIA diameter (OR: 0.87, 95% CI: 0.76-0.99, p=0.04), circumferential CIA calcification (OR: 0.97, 95% CI: 0.95-1.00, p=0.03), mean and maximal curvature of the preoperative aortoiliac trajectory (OR: 0.86, 95% CI: 0.79-0.94, p<0.01 and OR: 0.97, 95% CI: 0.95-1.00, p=0.03, respectively) and pre-to-postoperative decrease in mean curvature (OR: 1.11, 95% CI: 1.02-1.21, p=0.02). Midterm TE predictors were length (OR: 0.95, 95% CI: 0.89-1.01, p=0.08) and torsion maximum location (OR: 1.01, 95% CI: 0.99-1.01, p=0.10).

CONCLUSION

The present study confirms that treatment of infrarenal AAA with an Anaconda stent-graft is related to a relatively high TE rate which decreases with a pre-to-postoperative reduction in curvature and TI, and a larger degree of circumferential CIA calcification. In other words, more aortoiliac straightening and more circumferential CIA calcification may prevent TE development after EVAR with this stent-graft.

Impact of patient demographics and intraoperative characteristics on abdominal aortic aneurysm sac following endovascular repair

BACKGROUND

Endovascular aortic repair (EVAR) has become the preferred treatment for abdominal aortic aneurysm (AAA). Its main aim is to seal the perfusion of the aneurysmal sac and, thus, induce sac regression and subsequent aortic remodelling. Aneurysmal sac regression has been linked to the short- and long-term clinical outcomes post-EVAR. It has also been shown to be influenced by endograft device choice, with several of these available commercially. This review summarises and discusses current evidence on the influence of pre- and intraoperative factors on sac regression. Additionally, this review aims to highlight the device-specific variations in sac regression to provide an overall holistic approach to treating AAAs with EVAR.

METHODS

A comprehensive literature search was conducted using multiple electronic databases to identify and extract relevant data.

RESULTS

Female sex, >70 mm original sac diameters, higher pre-procedural fibrinogen levels, smoking and low intra-aneurysmal pressure were found to positively impact sac regression. Whereas renal impairment, ischemic heart disease, high intra-aneurysmal pressure and aneurysm neck thrombus negatively influenced sac regression. Patent lumbar arteries, age, statins and hypercholesterolaemia displayed conflicting evidence regarding sac regression. Regarding the EVAR endografts compared, newer generation devices such as the Anaconda mainly showed the most optimal results.

CONCLUSION

Sac regression following EVAR in AAA is an important prognostic factor for morbidity and mortality. Nevertheless, several pre- and intraoperative factors can have an influence on sac regression. Therefore, it is necessary to take them into account when assessing AAA patients for EVAR to optimise outcomes. The choice of EVAR stent-graft can also affect sac regression, with evidence suggesting that the Fenestrated Anaconda is associated with the most favourable results.

Patient longevity and survival with custom-made endovascular solutions: The Fenestrated AnacondaTM approach

BACKGROUND

Endovascular aortic repair (EVAR) has become the mainstay treatment for abdominal aortic aneurysms and is associated with excellent clinical outcomes. However, there remains a risk of complications requiring reintervention. Several EVAR devices exist commercially, yet, the Terumo Aortic Fenestrated Anaconda™ has demonstrated outstanding results. The main scope of this study is to evaluate survival/longevity, target vessel patency (TVP), endograft migration and reintervention following Fenestrated Anaconda™ implantation and discuss relevant literature.

METHODS

The current study represents a 9-year cross-sectional international analysis of custom-made Fenestrated Anaconda™ device. For the statistical analysis, SPSS 28 for Windows and R was utilised. Pearson Chi-Square analysis was used to assess differences in cumulative distribution frequencies between variables. Statistical significance for all two-tailed tests was set at p < 0.05.

RESULTS

A total of 5058 patients received the Fenestrated Anaconda™ endograft. The Fenestrated Anaconda™ was indicated either due to complex anatomy for competitor devices (n = 3891, 76.9%) or based on surgeon preference (n = 1167, 23.1%). Both survival and TVP were 100% during the first 6 postoperative years but dropped to 77.1% and 81% thereafter. In the complex anatomy indication group, cumulative survival and TVP were both 100% until year 7 post-EVAR when they decreased to 82.8% and 75.7%. In the other indication group, survival and TVP were also 100% during the first 6 years but plateaued at 58.1% and 98.8% in years 7-9 of follow-up. No cases of endograft migration and reintervention were recorded.

CONCLUSION

The Fenestrated Anaconda™ has been proven across the literature to be a highly effective EVAR endograft, as it has demonstrated excellent survival/longevity and TVP as well as minimal endograft migration and reintervention.

Correlative effect between sac regression and patient longevity following endovascular solution for abdominal aortic aneurysms: an international analysis

INTRODUCTION

Since the introduction of endovascular aortic repair (EVAR) it has become the mainstay treatment for abdominal aortic aneurysms. Several EVAR devices exist commercially, yet, the Terumo Aortic Fenestrated Anaconda™ endograft has demonstrated outstanding results. Evidence in the literature suggests that sac regression could be linked to patient survival and longevity. The main scope of this study is to evaluate sac regression and survival achieved using the Fenestrated Anaconda™ endograft and to discuss relevant literature.

MATERIALS AND METHODS

The current study represents a nine-year cross-sectional international analysis of custom-made Fenestrated Anaconda™ device. For the statistical analysis, SPSS 28 for Windows and R were utilised. Pearson chi-square analysis was used to assess differences in cumulative distribution frequencies between select variables. Statistical significance for all two-tailed tests was set at p < 0.05.

RESULTS

A total of 5,058 patients received the Fenestrated Anaconda™ in this study, either due to unsuitable/complex anatomy for competitor devices (n = 3,891) or based on surgeon preference (n = 1,167). A sac regression of 0-30% was observed in 4,772 (94.3%) over the first four years post-EVAR. Here, 99.6% of patients receiving the Fenestrated Anaconda™ due to unsuitable/complex anatomy for competitor devices and 76.8% based on surgeon preference had 0-30% sac regression. During years 5-9 of follow-up, all patients had 20-45% sac regression. Patient survival during the first six years post-EVAR was 100% but dropped to 77.1% in years 7-9. Survival differed between categorical patient subsets based on the indication.

DISCUSSION

The Fenestrated Anaconda™ has been proven to be a highly effective EVAR endograft. Evidence in the literature clearly demonstrates that sac regression is an accurate prognostic factor for patient survival and longevity.

Endovascular solutions for abdominal aortic aneurysms: A comparative review of clinical outcomes with custom-made endografts

BACKGROUND

The introduction of endovascular aortic repair has revolutionised the treatment of abdominal aortic aneurysms, replacing open surgical repair for the majority of elective cases due to its optimal morbidity and mortality. Several endovascular aortic repair stent grafts exist commercially, one of which is the Fenestrated Anaconda™ by Terumo Aortic which benefits from a very innovative design, unique custom-made approach and highly favourable results.

AIMS

The main scope of this narrative review is to provide a comprehensive overview of endovascular aortic repair clinical outcomes using the Fenestrated Anaconda™ stent-graft and comparing these with its market competitor, Zenith. This review will also examine the evidence in the literature on the Anaconda™'s custom-made approach.

METHODS

A comprehensive literature was conducted on several search engines including PubMed, Google Scholar, Ovid, Scopus and Embase to collate the evidence in the literature on clinical outcomes achieved with the Fenestrated Anaconda™ and Zenith including, but not limited to, survival, technical success, target vessel patency, endoleak, reintervention and aneurysm sac regression.

RESULTS

The Fenestrated Anaconda™ is associated with excellent results, including highly favourable survival, technical and clinical success and target vessel patency rates, very low need for reintervention or conversion, and minimal incidence of complications such as endoleak and endograft migration. The Fenestrated Anaconda™ also drives significant sac regression and aortic remodelling. In addition, its unique custom-made approach enables it to treat highly complex aortic anatomy as well as to 'rescue' failed competitor grafts.

CONCLUSION

The Fenestrated Anaconda™ has proven that it is a very safe, highly applicable and extremely effective device used for complex aortic and/or iliac pathology based on its novel design and outstanding track record of clinical outcomes.

Endovascular Treatment of Abdominal Aortic Aneurysm With Severe Angulation of Infrarenal Aortic Neck by Gore Conformable Endograft

INTRODUCTION

The aim of the study is to report a single-center experience with the Gore Excluder conformable endograft with active control system (CEXC Device, W.L. Gore and Associates, Flagstaff, AZ, USA) in abdominal aortic aneurysms (AAAs) with severe infrarenal neck angulation.

METHODS

All patients underwent EVAR with CEXC Device between September 2018 and 2020, were prospectively enrolled, and retrospectively analyzed. Anatomical details of the proximal aortic neck were evaluated. Early endpoints were the use of repositionability and angulation system, intraoperative unplanned cuff, technical success (TS), 30-day morbidity/mortality, and reintervention. Follow-up endpoints were type-I endoleaks, endograft migration, aortic neck dilatation, aneurismal sac shrinkage, survival (S), and freedom from reintervention (FFR).

RESULTS

Twenty-five patients were enrolled (median age: 80 [range = 60-90] years, median AAA diameter: 60 [range = 52-90] mm). All patients had severe infrarenal neck angulation (beta angle ≧ 60°), and 11 (44%) of those had neck beta angle ≧ 90°. Median infrarenal neck angle, length, and diameter were 70° (range = 60°-90°), 22 (range = 13-42) mm and 22 (range = 18-31) mm, respectively. Endograft repositioning system was employed in 15 (60%) cases and the median number of repositioning maneuvers was 1 (range:0-4). Active angulation system was used in 17 (68%) patients. The median proximal diameter of the main-body and oversize were 28 (range = 23-36) mm and 28% (range = 21%-38%), respectively. Proximal cuff was positioned in 1 (4%) patient. Technical success was achieved in all cases. Intraoperative and perioperative morbidity and mortality were 12% and 0%, respectively. Perioperative type-I/III and II endoleaks were observed in 0 and 4 (16%) patients, respectively. The median follow-up was 12 months (range: 3-30). One patient died at 12-month for AAA-unrelated causes. Abdominal aortic aneurysm-sac shrinkage and stability were observed in 9 (36%) and 15 (60%) cases, respectively. No type-I/III endoleak and reintervention occurred during the follow-up. One persistent type-II endoleak was observed. Estimated survival at 24 months was 92%.

CONCLUSION

According to the present data, the CEXC Device allows an excellent rate of TS in severe angulated aortic neck. This preliminary data, could increase the rate of patients eligible for EVAR.

Incidence and predictive factors for endograft limb patency of the Fenestrated Anaconda™ endograft used for complex endovascular aneurysm repair

OBJECTIVE

To describe the incidence, risk factors and outcomes of treatment for limb occlusion in patients treated for complex (thoraco-)abdominal aortic aneurysms (AAA) with the Fenestrated Anaconda™.

METHODS

Between June 2010 and May 2018, 335 patients underwent elective fenestrated aortic aneurysm repair in 11 participating centers using the Fenestrated Anaconda™ with a median follow-up of 14.3 months (IQR 27.4). The primary outcome measure was freedom-from-limb-occlusion. Secondary outcome measures were freedom-from-limb-related-reintervention, secondary patency, and risk factors associated with limb occlusion.

RESULTS

Thirty (9.0%) patients presented with limb occlusion during follow-up with freedom-from-limb-occlusion of 98.5%, 91.2%, and 81.7% at 30-days, 1 and 5 years, respectively. In 87% of cases, no obvious cause for limb occlusion was documented. Primary occlusion occurred within 30-days in 36.7% and within 1 year in 80.0%. Twenty-three (6.9%) patients underwent an occlusion-related reintervention; seven (23.3%) patients were treated conservatively. Freedom-from-limb-occlusion-related-reintervention at 30-days, one and five years was 97.8%, 93.2% and 88.6%, respectively. Secondary patency was 91.3% after 1-month and 86.2% after 1 and 5 years, respectively. Female sex (OR 3.27 - 95% CI 1.28 to 8.34, P = .01) was a statistically significant predictor for limb occlusion. A higher percentage of thrombus in the aneurysm sac appeared to be protective for limb occlusion (0% compared to <25%: OR 0.22 - 95% CI 0.07 to 0.63, P = .01; 0% compared to 25-50%: OR 0.20 - 95% CI 0.07 to 0.57, P = .00 and 0% compared to >50%: OR 0.08 - 95% CI 0.02 to 0.38, P = .00), as did iliac angulation (OR 0.99 - 95% CI 0.98 to 1.00, P = .04).

CONCLUSION

Limb occlusion remains a significant impediment of endograft durability in patients treated with the Fenestrated Anaconda™, especially in female patients. Controversially, a high aneurysmal thrombus load and a high degree of iliac angulation appeared to be protective for limb occlusion, for which no obvious cause could be identified.

Nineteen-year outcomes with the Anaconda stent graft system from two tertiary centers

OBJECTIVE

The Anaconda stent graft device presents peculiar and unique features in its design and deployment sequence, available on the market for many years with minor modifications, among different generations. The aim of this study was to assess the long-term, real-life, outcomes obtained in two high-volume centers with this endograft for infrarenal aortic aneurysms treatment over a period of 19 years.

METHODS

All patients treated with the investigated device between 2000 and 2019, with at least 1 year of follow-up, were entered into a prospective database and data were reviewed retrospectively. The long-term results were assessed according to the Kaplan-Meier method. Primary outcomes were overall survival, freedom from AAA rupture, and freedom from AAA-related death. Secondary outcomes were freedom from late reintervention, freedom from late conversion to open repair, freedom from late limb occlusion, and freedom from late EVAR failure.

RESULTS

A total of 260 consecutive patients were treated during the study period. Technical success was achieved in 98.5% (256/260) of the cases. Two perioperative deaths (0.8%) and four major complications (1.5%) were recorded. At a mean follow-up of 54 ± 38 months (summary follow-up index = 0.86), the late survival estimate was 94.8% at 1 year, 75.2% at 5 years, 50.5% at 10 years, and 43.3% at 13 years, with no case of late AAA rupture or late AAA-related death. Late freedom from conversion was 99.2% at 1 year, 96.9% at 5 years, 94.0% at 10 years, and 94.0% at 13 years. Freedom from late limb thrombosis was 96.8% at 1 year and 91.0% at 5, 10, and 13 years. Estimates of freedom from late reintervention was 95.6% at 1 year, 87.0% at 5 years, 77.4% at 10 years, and 77.4% at 13 years. Estimates of limb thrombosis at 11 years were significantly different in patients receiving or not intraoperative iliac kissing balloon maneuver with noncompliant angioplasty catheters (98.0% vs 88.4%; P = .029).

CONCLUSIONS

The Anaconda stent graft demonstrated effective and durable outcomes for AAA treatment over a 19-year period, with no case of late AAA rupture or AAA related death in the studied population. Late limb occlusion was the leading cause of reintervention; however, a positive prevention strategy was found in intraoperative kissing balloon, which was associated with significant reduced rate of iliac thrombosis over time.

Geometrical changes in Anaconda endograft limbs after endovascular aneurysm repair: A potential predictor for limb occlusion

The emergence of limb occlusion after endovascular aneurysm repair may be related to the conformational changes between the endograft structure and the patient's anatomy. This study analyzed detailed geometric changes of Anaconda endograft (Terumo Aortic, Inchinnan, Scotland, UK) limbs during the cardiac cycle-based computed tomography on serial imaging after graft implantation. Fifteen patients (mean age 72.8 ± 3.7 years; 14 men) underwent postoperative electrocardiogram-gated computed tomography scans according to a prospective study design between April 2014 and May 2017. Changes in curvature, length of the limbs, and distances between successive stent rings (inter-ring distance) of the endograft limbs during a 2-year follow-up period were quantified using meticulous image processing methods involving image registration, centerline extraction, and model-based stent-ring segmentation. From discharge to 24 months, mean curvature increased significantly by 9.6 m^-1 (standard deviation [SD], 11.1 m^-1; 95% confidence interval [CI], 3.4 to 15.8 m^-1; P = .002) for the right limbs and by 6.1 m^-1 (SD 9.4 m^-1; 95% CI, 0.8 to 11.5 m^-1; P = .21) for the left limbs. The length of the right limbs decreased significantly, by 9.5 mm (SD 7.6 mm; 95% CI, 3.5 to 15.6 mm; P = .002); the length of the left limbs decreased by 10.1 mm (SD 5.1 mm; 95% CI, 5.9 to 14.2 mm; P < .001). The minimal inter-ring distance decreased by 0.36 mm (SD 0.26 mm; 95% CI, 0.17 to 0.55 mm; P < .001) for the right limbs and 0.35 mm (SD 0.19 mm; 95% CI, 0.21 to 0.49 mm; P < .001) for the left limbs. Cardiac pulsatility-induced changes in curvature, limb length, and inter-ring distance were negligible (2%, 0.3% and 0.3%, respectively). Changes in the geometry of the Anaconda endograft limbs after endovascular aortic aneurysm repair were observed during a 2-year follow-up manifest as an increase in curvature, shortening of the stent-graft limbs, and a corresponding decrease in inter-ring distance. These stent-graft conformational changes could result in inward folding of the graft fabric, which may relate to the emergence of limb occlusion. Further investigation of these metrics in a larger cohort involving patients with and without occlusions may allow determination of their predictive value.

Outcomes of Endovascular Aneurysm Repair Using the Anaconda Stent-Graft

Purpose: To report outcomes of elective endovascular aneurysm repair (EVAR) using the Anaconda stent-graft in a tertiary vascular center. Materials and Methods: A retrospective study was conducted of 271 patients (mean age 71.5 years; 260 men) who underwent elective EVAR for abdominal aortic aneurysm using the Anaconda stent-graft from January 2006 to January 2017. Median aneurysm diameter was 58 mm (range 50-90). All patients were anatomically suitable for EVAR according to the 2003 version of the instructions for use. Follow-up included computed tomography angiography at 1, 6, and 12 months and yearly thereafter for the first 4 years and then every 2 years. Primary outcomes included technical success and 30-day aneurysm-related mortality and complications; secondary outcomes were overall and aneurysm-related mortality and aneurysm-related morbidity in follow-up. Results: The Anaconda stent-graft was implanted successfully in all patients. Primary and secondary technical success rates were 99.6% and 100%, respectively. Three patients (1.1%) died within 30 days of causes unrelated to the aneurysm, while 15 patients (5.5%) suffered perioperative complications. Median follow-up was 72 months (range 14-141). The overall type I endoleak rate was 4.7% (11 proximal, 2 distal). Late aneurysm-related complications were observed in 48 patients (17.3%); aneurysm-related mortality was 1.4% (n=4). Non-aneurysm-related mortality was 21.0% (n=57). Freedom from reintervention was 95.2% at 1 year, 98% at 2 years, and 90% at 6 years. There was no significant difference in the overall limb graft occlusion rate between the second- and third-generation devices. Conclusion: Results in our cohort study demonstrate that the Anaconda stent-graft has satisfactory early and late results with low aneurysm-related mortality.

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.

[New developements in endovascular infrarenal aortic aneurysm treatment]

CLINICAL/METHODICAL ISSUE

New technical developments in endovascular aortic repair (EVAR) have broadened the range of patients eligible for minimally invasive aneurysm treatment. Optimization of delivery sheaths and catheters by considerable downsizing of diameters, increase of pushability and stability combined with flexibility are important parameters.

PERFORMANCE

Especially patients characterized by small and tortuous iliac access vessels can nowadays be treated by EVAR. Ease and effectiveness of applicability guarantee safety and quality improvement, which results in better treatment of patients. Progress in stent-graft design with integrated options for repositioning, active positioning and aneurysm sealing facilitate treatment of angulated vessel segments or hitherto unsuitable sealing zones.

PRACTICAL RECOMMENDATIONS

Interventionalists have to be familiar with all available stent-graft materials and techniques. Profound knowledge helps to choose the best material for a patient's individual anatomy, confident application and long-term satisfactory results.

Contrast-enhanced ultrasound and/or colour duplex ultrasound for surveillance after endovascular abdominal aortic aneurysm repair: a systematic review and economic evaluation

BACKGROUND

Endovascular abdominal aortic aneurysm repair (EVAR) of abdominal aortic aneurysm (AAA) is less invasive than open surgery, but may be associated with important complications. Patients receiving EVAR require long-term surveillance to detect abnormalities and direct treatments. Computed tomography angiography (CTA) has been the most common imaging modality adopted for EVAR surveillance, but it is associated with repeated radiation exposure and the risk of contrast-related nephropathy. Colour duplex ultrasound (CDU) and, more recently, contrast-enhanced ultrasound (CEU) have been suggested as possible, safer, alternatives to CTA.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of imaging strategies, using either CDU or CEU alone or in conjunction with plain radiography, compared with CTA for EVAR surveillance.

DATA SOURCES

Major electronic databases were searched, including MEDLINE, EMBASE, Science Citation Index, Scopus' Articles-in-Press, Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE) and NHS Economic Evaluation Database from 1996 onwards. We also searched for relevant ongoing studies and conference proceedings. The final searches were undertaken in September 2016.

METHODS

We conducted a systematic review of randomised controlled trials and cohort studies of patients with AAAs who were receiving surveillance using CTA, CDU and CEU with or without plain radiography. Three reviewers were involved in the study selection, data extraction and risk-of-bias assessment. We developed a Markov model based on five surveillance strategies: (1) annual CTA; (2) annual CDU; (3) annual CEU; (4) CDU together with CTA at 1 year, followed by CDU on an annual basis; and (5) CEU together with CTA at 1 year, followed by CEU on an annual basis. All of these strategies also considered plain radiography on an annual basis.

RESULTS

We identified two non-randomised comparative studies and 25 cohort studies of interventions, and nine systematic reviews of diagnostic accuracy. Overall, the proportion of patients who required reintervention ranged from 1.1% (mean follow-up of 24 months) to 23.8% (mean follow-up of 32 months). Reintervention was mainly required for patients with thrombosis and types I-III endoleaks. All-cause mortality ranged from 2.7% (mean follow-up of 24 months) to 42% (mean follow-up of 54.8 months). Aneurysm-related mortality occurred in < 1% of the participants. Strategies based on early and mid-term CTA and/or CDU and long-term CDU surveillance were broadly comparable with those based on a combination of CTA and CDU throughout the follow-up period in terms of clinical complications, reinterventions and mortality. The economic evaluation showed that a CDU-based strategy generated lower expected costs and higher quality-adjusted life-year (QALYs) than a CTA-based strategy and has a 63% probability of being cost-effective at a £30,000 willingness-to-pay-per-QALY threshold. A CEU-based strategy generated more QALYs, but at higher costs, and became cost-effective only for high-risk patient groups.

LIMITATIONS

Most studies were rated as being at a high or moderate risk of bias. No studies compared CDU with CEU. Substantial clinical heterogeneity precluded a formal synthesis of results. The economic model was hindered by a lack of suitable data.

CONCLUSIONS

Current surveillance practice is very heterogeneous. CDU may be a safe and cost-effective alternative to CTA, with CTA being reserved for abnormal/inconclusive CDU cases.

FUTURE WORK

Research is needed to validate the safety of modified, more-targeted surveillance protocols based on the use of CDU and CEU. The role of radiography for surveillance after EVAR requires clarification.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016036475.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Incidence and Treatment of Limb Occlusion of the Anaconda Endograft After Endovascular Aneurysm Repair

Purpose: To evaluate the incidence and treatment of limb occlusions of the second- and third-generation Anaconda endografts. Methods: A single-center retrospective study was conducted involving 317 consecutive patients (mean age 76 years; 289 men) who underwent endovascular aneurysm repair for elective asymptomatic, symptomatic intact, and ruptured infrarenal abdominal aortic aneurysm with 2 versions of the Anaconda device. From September 2003 to July 2011, the second-generation device was used in 189 patients (mean age 77 years; 169 men) and from July 2011 to September 2015, the third-generation device was implanted in 128 patients (mean age 75 years; 120 men). The rates of limb occlusion were compared between groups and according to compliance with the instructions for use (IFU); predictors were sought in multivariate analysis. The results of the latter are given as the hazard ratio (HR) and 95% confidence interval (CI). Results: Kaplan-Meier freedom of occlusion estimates for second- and third-generation devices, respectively, was 96.6% and 95.0% at 1 year, 89.9% and 95.0% at 2 years, and 86.5% and 88.6% at 5 years. There was no significant difference in overall occlusion rate between the second-generation devices (p=0.332) or with regard to use within the IFU (p=0.827); however, there was a clinically relevant decrease in the occlusion rate for elective patients treated with the third-generation device (6.4% vs 13.1%, p=0.077). There was an increase in the occlusion rate when the iliac limb diameter was ≤13 mm. In multivariate analysis, the only independent predictor of limb occlusion was a small distal prosthesis diameter (HR 0.732, 95% CI 0.63 to 0.86, p<0.001). Symptomatic nonruptured and ruptured abdominal aortic aneurysm (AAA) interventions had an almost 2-fold increased risk of occlusion (HR 1.95, 95% CI 0.93 to 4.11, p=0.078), though this did not reach statistical significance. Conclusion: The Anaconda design has proven effectiveness in AAA exclusion in daily practice inside the IFU. However, efforts could be made to further reduce the limb occlusion rate.

Endovascular Management of a Distally Migrated Bifurcated Endograft with a New Bifurcated Endograft

A 75-year-old man presented with abdominal and lumbar pain 6 years after previous endovascular repair of an abdominal aortic aneurysm. At the time of the initial operation, the aneurysm measured 6.0 cm in maximum diameter and a bifurcated Anaconda (Vascutek) endograft had been implanted. This time, computed tomography showed a distally migrated endograft which had been folded within the sac and the aneurysm measured 8.4 cm in maximum diameter. We opted to treat this by endovascular means deploying a new bifurcated endograft with suprarenal fixation within the old one. We consider the different management options and discuss the associated technical difficulties.

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.

Results of the French Multicentric Study of ANACONDA™ Fenestrated Endografts in the Treatment of Complex Aortic Pathologies (EFEFA Registry)

BACKGROUND

Most of the experience on fenestrated endovascular aneurysm repair involves the custom-made Zenith^® endograft (Cook). The fenestrated Anaconda^® endograft (Vascutek) was introduced with the potential advantages of complete repositioning and lack of stent material on the main aortic body for more versatility. However, few data are available. Our objective was to assess its mid-term results in the treatment of complex aortic aneurysms.

METHODS

Consecutive patients treated with the custom-made fenestrated Anaconda endograft in France and the Principality of Monaco, from December 2010 to October 2015, were included.

RESULTS

Eighty-six patients were included over 16 centers (82 men, mean age 73.4 ± 8.1 years, 16 (18.6%) symptomatic aneurysms). The repositioning system was used in 68 cases (79.1%). Two hundred ninety-two visceral/renal vessels were targeted, with a mean number of 3.4 ± 0.6 target vessels/patient and a successful reconstruction in 99.3% of the cases (290/292 vessels). Perioperative technical success was achieved in 86.0% (74/86 patients). In-hospital and 30-day mortality rates were 3.5% (3 patients) and 7.0% (6 patients), respectively. At 12 and 24 months, estimated overall survival rate was 88.3% and 85.2%, target vessel's patency rate was 97.2% and 96.3%, and freedom from aneurysm-related reintervention rate was 96.3% and 88.0%, respectively. At 24 months, there were 7 type II endoleaks (12.7%) and a significant reduction in aneurysm maximum transverse diameter in 70.4%. Five limb occlusions occurred at 1-year and 1 at 2-year follow-up (7.0%).

CONCLUSIONS

The fenestrated Anaconda stent-graft system offers acceptable technical success rates, mid-term efficacy, and durability with respect to aneurysm sac regression, target vessel patency, overall mortality, and reintervention rates. Long-term results are still awaited, until then, the rate of graft limb occlusion is of concern and should be further investigated, especially in case of particularly complex aortic anatomies.

Patient selection for endovascular sac sealing of abdominal aortic aneurysm

Endovascular sealing is a developing technique for treatment of abdominal aortic aneurysm that draws on novel concepts utilizing polymer filling of endobags within the aorto-iliac lumen. The morphologic indications and patient selection, while similar to those of endovascular aneurysm repair, differ in some regards. The Instructions for Use for the Nellix sealing device may expand the indications for aneurysm treatment and are closely scrutinized in this article. The authors draw on current evidence and their own experience and opinion in the discussion around appropriate patient selection and its influence on outcomes after endovascular aneurysm sealing. A recommendation for stricter adherence to Instructions for Use in the early phase of clinical experience is made, with acknowledgement that the natural evolution of endovascular aneurysm sealing may involve more challenging cases.